Scientific amcvican ^cricsi 



Home Mechanics 

For Amateurs 




BY 



GEORGE M. HOPKINS 

Author of ^'^ Experimental Science'' 



3" J J 



MuNN & Co., Publishers 

SCIENTIFIC AMERICAN OFFICE 

NEW YORK, 1903 



H 



Two CoPi<ie Bfc.QKiweaL> 

mrr 'it \pm 

GLASS ft YXn- Mo. 
COPY B, 



Copyright, 190?, by Munn & Co. 
All rights reserved. 

Entered at Stationers' Hall, London, England, 






Press of Andrew H. Kellogg 
New Yokk, U. S. A. 



^/r 



PREFACE 



SPECIAL INTEREST ahvays attaches to a post- 
humous work. It is not always, however, that 
a work of this character possesses equal merit 
with one entirel}^ completed before the death of the 
author. As a rule such works have not had the ad- 
vantage of the final perusal and correction by the 
author. Such has not, however, been the case in the 
present instance, for the following work by the late 
George M. Hopkins, was completed before his death. 
Tl ere is no doubt, however, that this volume will come 
as a surprise to thousands Avho have closely followed 
Mr. Hopkins' Avork, and who have enjoyed making 
the many experiments described by him. The present 
volume contains much matter which has never before 
appeared in print, and some articles Avhich have al- 
ready been published in the Scientific American. The 
object of the work is to furnish food for thought to the 
amateur, and to give him suggestions Avhereby he may 
pass many pleasant hours in his Avork-shop. 3Ir. Hop- 
kins Avas an expert mechanic. One of his chief pleas- 
ures Avas to make experiments at his home in his Avell- 
equipped Avork-shop and laboratory, and the Avork 
described in the present volume is nearly all the result 
of experiments made by him during such ^Mdle" hours. 
It has been the intent of the author to make the present 



PEEFACE. 

work as suggestive as possible. No complicated ap- 
paratus is required iu carrying out the experiuieuts 
described. Any one with ordinary mechanical inge- 
nuity and having a lathe and a few tools can make most 
of the experiments described in these pages. 

A few articles by other authors have been included 
as they are germane to the scope of the book. It is 
hoped that ''Home ^Mechanics for Amateurs" will prove 
helpful to as. many thousands as has ''Experimental 
Science." 



Table of Contents 



PART I. 

Wood- WoR K I n g 

An Inexpensive Turning Lathe. Turning. Wood-Working on a 
Lathe. Work Bench and Tools for Woodwork. Whittling. 
Different Shapes of Saw Teeth and the Way they Cut. A 
Wrinkle in Sawing. Wood Carving 1 



PART n. 

How TO Make Household Orxamexts 

Home-made Grilles and Gratings. Wall Ornaments. Pseudo- 
Ceramics. Imitation of Majolica. Stained Glass and Ob- 
jects of Wire Cloth. Japanese Portiere or Curtain. 
Repousse. An Easy Method of Producing Bas-reliefs. 
Ornamental Iron Work for Amateurs. Some Things in 
Wire. Some Things in Burnished Brass. Forming Plaster 
Objects 31 



PART III. 

Metal-Workixg 

Sawing Metals. Soldering. Grinding and Polishing. Silver 
Work. Metal Foot Lathe. Drills and Drilling. Centering 
and Steadying. Chucking. Metal Turning. Chasing and 
Knurling. Rotary Cutters. Easily made Slide Rest. In- 
dex Plates for Gear Cutting. Gear Cutting Apparatus. 
Hints on Model Making. Metal Spinning 89 



TABLE OF CONTENTS 

PART IV. 

Model Engines and Boilers 

A Home-made Steam Engine. A Safe Way of Running a Small 
Engine. A Miniature Caloric Engine. An Inexpensive 
Water Motor 169 



PART V. 

Meteorology 

Self-Recording Instruments. What may be learned by the Use 
of the Meteorological Instruments. A Weather Vane. 
Wind Pressure Gauge. Rain Gauge. A Metallic Ther- 
mometer. A Simple Hygroscope. A Mercurial Barometer. 187 



PART VI. 

Telescopes and Microscopes 

How to make a Telescope. The Microscope 207 



PART VII. 

Electricity 

Practical Primary Battery. Electric Lighting for Amateurs. 
The Electric Chime. Home-made Electric Night Lamp. 
An Electrical Cabinet. Simple Electric Motor. Small 
Electric Motor for Amateurs. How to make a Sewing 
Machine Motor without Castings. A Design for an Electric 
Launch Motor. How to make an Edison Dynamo and 
Motor. The Utilization of 110 Volt Electric Circuits for 
Small Furnace Work. Recording Telegraph for Amateurs. 
How to make a Telephone 227 



PART I. 

WOOD-WORKIISTG 

AN INEXPENSIVE TURNING LATHE 

THE BOY who has a turning lathe can readily 
make many things which he might not feel 
disposed to buy ; for example, he can make tops, 
ninepins, and ornamental and useful objects 
without much trouble and with very little expense. 
The ancient lathe consisted of two conical points, sup- 
ported in position by suitable standards, and the work 
to be done was whirled on these points b}^ means of a 
strong cord wrapi)ed once around the stick to be turned, 
with the upper end attached to a spring pole and 
the lower end secured to a treadle. The lathe we are 
about to describe is one remove from this primitive 
lathe of the olden time. It has the two standards with 
points or dead centers, as thej would be called by ma- 
chinists, but one of the points projects far enough from 
the standard to receive a hard wood pulley, having 
inserted in its side, at diametrically opposite points, 
two spurs, which enter the end of the piece of wood 
to be turned, so that when the pulley is revolved by 
a belt, the wood will be turned on the centers. 

This lathe is made almost entirely from strips of 
hard Avood, 1 inch thick and 2^ inches wide. These 
strips can be easily furnished by any carpenter, cabinet 
maker or wagon maker, and an old table may be used 
for the frame. 

The bed-piece is made of two such strips, 2 feet long, 
and a block of the same material, 1 inch square and 2 

[IJ 



2 HOME MECIIAXICS FOR AMATEURS 

inches long, at one end is placed between the strips 
and held in place bv wood screws. A piece of thick 
j)aper is placed between the block and one of the strips, 




Fig. 1. An Easily Constructed Wood Lathe. 



to make the space between the strips a little wider than 
the thickness of the block. 

To each end of the bed is secured a foot, consisting 
of a piece of the same strip, 6 inches long. These are 
secured by wood screws passing upward through holes 



HOME MECHAmCS FOR AMATEUES 3 

in the lower edoe of the foot, the holes being deeply 
countersunk to let in the heads of the screws. 

The head stock and tail stock are nearly alike, in 
so far as the wood work is concerned. Each is formed 
of three pieces of the strip from Avhich the bed is 
made. To opposite sides of a central piece, 74 inches 
long, are secured side pieces 4 inches long, by means 
of screws. These side pieces must of course be square 
on the end so that they will set squarely on the bed 
when the projecting end of the central piece is inserted 




Fig. 2. Work in the Lathe. 

in the slot of the bed. The loAver end of the center piece 
is mortised to receive a Avooden key or wedge, which 
clamps the tail stock to the bed. In the tail stock. -J 
inch from the top, is bored a hole in which is inserted 
a large wood screw, the point of which is filed conically, 
as shown. In the head stock is also bored a hole 
corresponding with that of the tail stock, to receiA^e a 
large wood scrcAv, i or 5-16 inch in diameter. The head 
of this screw is cut off, and the head (^nd is filed off 
conically. This point should project about an inch 
from the head stock, and to the plain, smooth pro- 



4 HOME MECHANICS FOE AMATEUES 

jeeting part of the screw is fitted a small grooved 
pulley about 1^ inches in diameter at the bottom of 
the groove. The pulley should be of Babbitt metal 
or type metal. In the side of the pulley, about J 
inch from the hole, are inserted two small screws, about 
f inch long, which are allowed to project ; these screws 
are filed to form chisel-edged spurs for driving the 
work in the lathe. The points should project as far 
as the point of the conical end of the large screw. 

The lower end of the head stock — which is about 2^ 
inches long — is inserted between the strips forming 
the bed, and fastened with screws; a piece of paper 
being inserted to increase the space between the strips, 
so that the tail stock can be moved easily. 

The wood to be turned has a small hole^ — say, ^ inch 
— bored in the center at each end, and is placed be- 
tween the centers; the tail stock having been clamped 
in the proper position, the tail screw is turned with 
a screw driver until it is forced a short distance into 
the end of the stick. Then the stick is driven for- 
ward on to the center, and spurs of the head stock, and 
the screw in the tail stock is turned so as to hold the 
stick, but not enough to create friction. A drop of oil 
should be put on each center, and the pulley should 
be oiled. 

The rest on which the gouge or chisel is placed while 
the turning is being done consists of a piece of the 
wooden strip with a slot in it to allow a 5-inch car- 
riage bolt to pass through. This bolt extends through 
the slot of the bed, and through a block or washer be- 
low. A wing nut is placed on the bolt so that the rest 
may be clamped in any desired iDosition. To the end of 
the slotted piece is secured a short piece of the wooden 



HOME MECHAmCS FOR AMATEURS 5 

strip by two screws passing through the slotted piece 
and into the wood. The wooden rest should be beveled 
as shown. 

Jt must be frankly admitted this lathe is not an 
elegant machine to look at, but it is capable of turning 
out quite reputable small work. 

Having made the lathe, it will be necessary to pro- 
vide some means to drive it. In almost every city and 
town may be found old sewing machine tables, which 
have been taken in trade as old iron. One of these can 
be bought cheaply, and when the treadle is turned 
around and a round leather belt applied to the lathe 
pulley and the sewing machine wheel, the arrangement 
is complete. 

Some one may be found good enough to loan a sew- 
ing table for the purpose. In this case, an assistant 
will be obliged to work the treadle while the turning 
is being done. 

As the flywheel should be heavy, not less than 20 
pounds, and as it should be about 20 inches in diameter 
to secure the desired speed, it is perhaps better to fit 
up the lathe with a wheel and table better adapted 
to it than a sewing machine wheel and table would be. 

The lathe shown in the illustration is mounted on a 
common kitchen table of the smallest size. In this 
case, an old wheel is selected at the junk shop; one 
with a groove in the edge is to be preferred, but a flat 
rim will answer. The one here shown has a flat face 
and is provided with a shaft, a crank and standards. 
The standards are inverted and fastened with screws 
to the under side of the table top. 

A strip of board extending lengthwise of the table 
is attached to the rear legs with screws, and the piece 



6 



HOME MECHANICS FOR AMATEURS 



of board forming the treadle is hinged to it in position 
to receive the screw Avhich passes through the lower 
end of the pitman rod or connecting rod, the npper 
end being apertnred to receiA e the crank pin. A ronnd 
leather belt is used in this case. 

The tools for turning are not very expensive; with 
two gouges and one or two flat chisels a great variety 
of work mav be done. 



TURNING 

There is no secret in turning. It requires a great 
deal of practice to become an expert, but beyond acquir- 
ing the first principles nothing further than practice 
is required. When reducing a piece of wood to the 




Fig. 3. Lathe Turning Tools. 



desired approximate size, the gouge is held on the 
rest with its handle-end inclined downward at an angle 
of about 60° with the horizontal, the rest being near 
the work, and the gouge is moved back and forth on the 



HOME MECHANICS FOR AMATEURS 7 

rest, takiiiij; off a slii»lit sliaviug each lime it is moved. 
The handle is held in the right hand, while the blade 
of the gouge is held in the left hand, with the thumb 
pressing on the coneave side. If a plain cylinder is 
required it may be made by using the flat chisel, lay- 
ing the beveled edge on the work in such a manner as 
to produce a drawing cut as the wood passes the edge. 
If the work is to be cut into at right angles or at any 
other angle, the chisel is placed on its edge on the rest 
and held firmly while moving it forward. 

In cutting concave forms the gouge is made to make 
a drawing cut by placing it partly on its edge on the 
rest. It will be found necessary in either of these 
cases to hold the tool very firmly on the rest to pre- 
vent the edge from drawing itself forward on the wood 
and spoiling the work. By practice the art of wood- 
turning can be readily acquired even by the use of 
the ^'Simple Lathe." 

For hard wood and ivory a different class of tools 
is required. The chisels are all flat, not oblique; some 
of them have edges that are square across; some have 
V-shaped points and others are round-nosed. For 
under-cuts and odd work, special tools are bent at 
different angles. Flat work, such as rosettes, etc., is 
chucked upon the face plate, or attached with screws 
to a board fixed to the face plate. 

In finishing work the use of fine sandpaper is admis- 
sible, but it never should be used to correct poor turn- 
ing. Wood work, when smoothed a little with fine 
sandpaper, may be finished by applying to it with a 
cloth a mixture of shellac varnish and linseed oil, in 
proportion of about one part of oil to two of shellac. 
Only a little is applied to the cloth at one time, the pol- 



8 HOME MECHANICS FOR AMATEURS 

ish being well shaken before it is applied. The work in 
the lathe is rapidly revolved until it is brightly polished 
and the shellac varnish is hard. If desired, the work 
may be stained before it is polished. The stains are 
readily obtainable, and are described in the "Scientific 
American Cyclopedia of Receipts, Notes and Queries." 



WOOD-WORKING ON A LATHE 

It is not the intention of the writer to enter largely 
into the subject of wood-working, but simply to sug- 
gest a few handy attachments to the foot lathe which 
will greatly facilitate the operations of the amateur 







Fig. 4. Saw Table 



IH^^^^^^^^^ " 



wood worker, and will be found very useful by almost 
any one working in wood. It is not an easy matter 
to split even thin lumber into strips of uniform width 
by means of a handsaw, but by using the circular saw 
attachment, shown in Fig. 4, the operation becomes 
rapid and easy, and the stuff may be sawed or slit at 
any desired angle or bevel. The attachment consists 
of a saw mandrel of the usual form, and a wooden table 
supported by a right angled piece. A, of round iron 



HOME MECHAOTCS FOR AMATEURS 9 

fitted to tlie toolpost aud clamped by a woodeu cleat, 
B, which is secured to the under side of the table, 
split from the aperture to one end, and provided with 
a thumbscrew for drawing the parts together. By 
means of this arrangement the table may be inclined 
to a limited angle in either direction, the slot through 
which the saw projects being enlarged below to admit 
of this adjustment. 

The back of the table is steadied by a screw which 
rests upon the back end of the tool rest support, and 
enters a block attached to the under side of the table. 
The gauge at the top of the table is used in slitting and 
for other purposes which will be presently mentioned, 
and it is adjusted by aid of lines made across the table 
parallel witli the saw. 






Fig. 5. 
Saw between beveled Washers. 



Fig. 6. Fig. 7. 

Moulding Knives. 



For the purpose of cross-cutting or cutting on a 
bevel a thin sliding table is fitted to slide upon the 
main table, and is provided with a gauge which is 
capable of being adjusted at any desired angle. For 
cutting slots for panels, etc., thick saws may be used, 
or the saw may be made to wabble by placing it be- 
tween two beveled washers, as shown in Fig. 5. 

The saw table has an inserted portion, C, held in 
place by two screws which may be removed when it 
is desired to use the saw mandrel for carrying a sticker 
head for planing small strips of moulding or reeding. 



10 



HOME MECHANICS FOR AMATEURS 



(Figs. G and T.j Tlu' head for lioldiiig the moulding 
knives is best made of good tough brass or steam metaL 
The knives can be made of good saw steel about ^ inch 
thick. They may be filed into shape and afterward 
tempered. They are slotted and held to their places 
on the head by means of i-inch machine screws. It is 
not absolutely necessary to use two knives, but when 
only one is employed a counterbalance should be fas- 
tened to the head in place of the other. All kinds of 
moulding, beading, tonguing and grooving may be done 
w^ith this attachment, the gauge being used to guide the 




Turning Fluted Work. 



edge of the stuff. If the boards are too thin to sup- 
port themselves against the action of the knives they 
must be backed up by a thick strip of wood planed 
true. The speed for this cutter head should be as great 
as possible. 

Fig. 8 shows an attachment to be used in connection 
with the cutter head and saw table for cutting straight, 
spiral or irregular flutes on turned work. It consists 
of a bar, D, carrying a central fixed arm, and at either 
end an adjustable arm, the purpose of the latter being 
to adapt the device to work of different lengths. The 
arm projecting from the center of the bar, D, sup- 



IIO]\rE MECHANICS FOE AMATEUES 



11 



ports an arbor Iia\'inj;al one end a socket foi* rccciviii^ii^ 
the twisted iron bar, E, and at the other end a center 
and a short finder or pin. A metal disk havini;- three 
spurs, a central aperture and a series of holes equally 
distant from the center and from each other, is at- 
tached by its spurs to the end of the cylinder to be 
fluted, and the center of the arbor in the arm, D, enters 
the central hole in the disk while its finger enters 




Fig. 9. 
Moulding Irregular Work. 



Fig. 10. 



one of the other holes. The opposite end of the cylin- 
der is supported by a center screw. A fork attached 
to the back of the table embraces the twisted iron, E, 
so that as the wooden cylinder is moved diagonally 
over the cutter it is slowly rotated, making a spiral 
cut. After the first cut is made the finger of the arbor 
is removed from the disk and placed in an adjoining 
hole, when the second cut is made, and so on. 



12 



HOME MECHANICS FOE AMATEUES 



Figs. 9 and 10 show a convenient and easily made 
attachment for moulding the edges of irregular work, 
such as brackets, frames, parts of patterns, etc. It 
consists of a brass frame, F, supporting a small man- 
drel turning at the top in a conical bearing in the 
frame, and at the bottom upon a conical screw. A very 
small grooved pulley is fastened to the mandrel and 
surrounded by a rubber ring which bears against the 
face plate of the lathe, as shown in the engraving. The 
frame, F, is let into a wooden table supported by an 




Fig. 11. Scroll Saw. 



iron rod which is received by the tool rest holder of 
the lathe. The cutter, G, is made by turning upon a 
piece of steel the reverse of the required moulding, and 
slotting it transversely to form cutting edges. The 
shank of the cutter is fitted to a hole in the mandrel and 
secured in place by a small set screw. The edge of the 
work is permitted to bear against the shank of the cut- 
ter. Should the face plate of the lathe be too small to 
give the required speed, a wooden disk may be attached 
to it by means of screws and turned off. 



HOME MECHANICS FOR AMATEURS 



13 



Fig-s. 11, 12, aud 13 represent a cheaply and easily 
made scroll saw attachment for the foot lathe. It is 
made entirely of wood and is practically noiseless. The 
board, H, supports two uprights, I, between which is 
pivoted the arm, J, whose under side is parallel with 
the edge of the board. A block is placed between the 
uprights, I, to limit the downward movement of the 
arm, and the arm is clamped by a bolt which passes 
through it and through the two uprights and is pro- 
vided with a wing nut. 

A wooden table, secured to the upper edge of the 
board, H, is perforated to allow the saw to pass 




Fig. 12. 
Details of Saw. 



Fig. 13. 



through, and is provided with an inserted hard- 
wood strip which supports the back of the saw, 
and which may be moved forward from time to 
time and cut off as it becomes worn. The upper 
guide of the saw consists of a round piece of 
hard wood inserted in a hole bored in the end 
of the arm, J. The upper end of the saw is secured in a 
small steel clamp pivoted in a slot in the end of a 
wooden spring secured to the top of the arm, J, and the 
lower end of the saw is secured in a similar clamp 
pivoted to the end of tlie wooden spring, K. Fig. 13 
is an enlarged view showing the construction of clamp. 
The relation of the spring, K, to the board, H, and to 



14 HOME MECHANICS FOPt z\MATEUES 

the other part is showu iu Fig. 12. It is attached to the 
side of the board and is pressed upward by au adjust- 
ing screw near its fixed end. 

The saw is driven by a wooden eccentric phiced on the 
saw mandrel shown in Figs. 4 and 5, and the spring, K, 
always pressed upward against the eccentric by its own 
ehisticity, and it is also drawn in an upward direction 
by the upper spring. This arrangement insures a con- 
tinuous contact between the spring, K, and the eccen- 
tric, and consequently avoids noise. The friction sur- 
faces of the eccentric and spring may be lubricated 
with tallow and plumbago. The eccentric may, with 
advantage, be made of metal. 

The tension of the uppc^r spring may be varied by 
putting under it blocks of ditferent heights, or the 
screw which holds the back end may be used for this 
purpose. 

The saw is attached to the lathe by means of an iron 
bent twice at right angles, attached to the board, H, and 
fitted to the tool rest support. The rear end of the saw- 
ing apparatus may be supported by a brace running to 
the lower part of the lathe or to the floor. 

The simple attachments above described will enable 
the possessor to make man^^ small articles of furniture 
which he would not undertake without them, and for 
making models of small patterns they are almost in- 
valuable. 



WOEK BENCH AND TOOLS FOE WOODWORK 

The first thing rexpiirc^d by the amateur workman is 
a bench with a few tools for wood working. The bench 
need not necessarily be a long and heavy structure like 



HOME MECHAmCS FOE AMATEUES 15 

a carpenter's bench, as the work to be done by the ama- 
teur is mostly small, requiring but little material and 
small room. A table like that shown in connection 
with the simple lathe will answer, or the rear portion 
of the lathe table may be used as a bench. A small 
wooden vise is secured to the side of the table near the 
left hand end, and in the top of the table is inserted a 
common flat headed wood screw, which may be screwed 
down even with the top of the table, or raised i or :i 
inch, as the work ma^^ require. This screw takes the 
place of the usual bench dog, and holds the end of a 
piece of wood while it is being planed. Two planes are 
required to begin with, a jack plane and a smooth plane. 
A good fine cross-cut saw will probably answer for 
all ordinary sawing, and it may be used as a rip saw 
when only a little of this kind of work is required. Two 
chisels, one f inch, the other ^ inch, and two gouges of 
about the same width, will be needed. A hammer and 
a screwdriver, together with a brad awl and a foot rule 
complete an outfit that will enable the owner to do a 
great deal of work. 

Of course a good oil stone should be at hand for 
sharpening the tools, and they should be kept shai'p. 

Chisels and plane irons must be held at an angle of 
about 60° to the surface of the stone and moved back 
and forth on the stone until an edge is produced. The 
straight side of the tool must be kept from the oil stone. 

While the tool is being sharpened the oil stone must 
be lubricated with a few drops of sewing machine oil or 
bicycle oil. When the tools need grinding it is advis- 
able to have the Avork done by a competent workman. 

The plane irons are set so that the edge is seen all the 
A\'av across the Avood of the plane and secured by driv- 



16 HOME MECHANICS FOR AMATEURS 

ing in the wedge. If the tool projects so as to make a 
thick shaving, the wedge is loosened slightly and tlie 
iron is made to rise slightly by tapping with a hammer 
on the top of the plane. The iron may be adjusted lat- 
erally by tapping the iron on one edge or the other near 
the top, and it may be forced downward by a few light 
taps on the upper end. 

After some observation — ever}^ boy has opportunities 
for observation — and after practice, the amateur will 
be able to do an ordinary job of carpentry, and he will 
seek after a few more tools, such for example as a try- 
square, a bit-stock and a few bits, a few clamps and a 
glue pot. He can then enter into the work heartily, and 
not only make needed repairs, but construct many plain 
little articles such as boxes Avith hinged covers, cabi- 
nets, screen frames, etc. The main requirements are to 
construct each part as carefully as possible, to assem- 
ble the parts with equal care, and to never use plugs or 
putty, or in other ways patch up for bad workmanship. 
If a mistake is made, it is generally better to throw the 
part away and begin again rather than to patch. 



WHITTLING 

The boy who is a good whittler will make a good me- 
chanic, or will at least understand mechanics well 
enough to know a good job from a poor one, and will 
be able to help himself in many an emergency. Real 
proficiency with a jack-knife implies a knowledge of 
mechanics and exhibits an ai^titude for mechanical 
work which only needs opportunity and encouragement 
to reach a useful stage of development. 

A jack-knife is a very simple tool, but without doubt 



HOME MECHAXICS FOR AMATEUKS 17 

it is more generally useful tliau au}^ other. For whit- 
tling, an ordinary two or four-bladed knife should be 
selected. It should have a good-sized handle and its 
blades should be fine and well tempered. With the 
knife should be purchased a fine, sharp oil stone, and 
the knife should be kept sharp, as it is impossible even 







\, 






^ 




'K 






^-J 




^E,^ ^'^^^S 




""^ 


^^^^Tz 


T~IZ^^ 


^^g 




1 




^1 


i 


1 



Fig. 14. Knives adapted for Whittling. 

for an expert workman to do good work with a dull 
knife. 

In sharpening the knife, the blade should be kept at 
an angle of about 20° with the face of the 
stone and rubbed back and forth the full length of the 
stone about an equal number of times for opposite sides 
of the blade, until it appears to be sharp, the stone 
meantime being lubricated with water or oil ; then it 
may be stropped like a razor on a strip of leather until 
it is literally as sharp as a razor. 

In whittling curious and ornamental objects, sea- 
soned straight-grained white pine should be selected. 



18 HOME MECHANICS FOR AMATEUES 

The piece should be a little larger than the finished 
work, and the design should be laid out in pencil on one 
side of the block, when it can be sawed out with a scroll 
saw. If the form can be traced on the edge of the work 
much whittling may be avoided by doing more sawing. 
The knife work may now proceed. It is well to begin 
with the heavier portions and finish with the lighter 
portions. 

As much should be done as possible without the use 
of sand paper. If it can all be done without sand paper 
so much the better. It will sometimes be found nec- 
essary to put on the finishing touches with a piece of 
very fine sand paper. Blades of different forms are 
found useful, and in some kinds of work a penknife 
blade which has been broken off rather short will prove 
exceedingly useful when the blade has been repointed. 

The saw used for shaping the work may be like the 
one on pages 12 and 13, or one of the small scroll saw- 
ing machines so much in use at one time would be still 
better. 

A very pretty example of whittling is the chain whose 
links are formed from a single bar of wood of 0-shaped 
cross section. To make a good job the bar should be 
evenly spaced, and the links drawn on the sides of the 
bar. Then holes are bored diagonally through the bar. 
At the angle the cutting proceeds slowly and cautious- 
ly, finishing the link as far as possible before it is cut 
loose. If any sandpapering is to be done it should be 
done as far as possible before the link is cut loose. In 
the example shown, only a iDortion of the wooden bar 
has been formed with links, the remainder being left 
to give an idea of the method. 

It is more difficult to whittle a pair of pliers from a 



HOME ]\[ECHAXICS FOR AMATEUES 19 

single piece of wood, so that the jaws work freely, and 
at the same time the joints are neat. 




Fig. 15. Examples of Whittled Work. 

The blank for the pliers is sawed from ^-inch pine. 
The sides of the pliers where the joint is to be formed 
are finished and the joint is carefnlly laid out in fine 



20 HOME MECHANICS FOR AMATEURS 

lines. Then with a very thin knife blade inserted from 
each side the central portion of the joint is cut through ; 
thin incisions are made in the sides to intersect the 
other cuts. The jaws of the pliers are carefully sep- 
arated by cutting from either side, and the cuts which 
separate the inside piece are then made with great care. 
The outside of the jaws and the handles are now fin- 
ished. In cutting the joint the wood is somewhat com- 
pressed by the insertion of the knife, and the joint ap- 
pears badly made. By soaking the wood in water for 
a half-hour or so the wood resumes its normal condi- 
tion, and the joint becomes tight. When the wood is 
dry the finishing may be done with a knife and with 
fine sand paper. 

The tower containing the balls and the revolving 
spindle is cut from a single bar of wood, with the balls 
and spheroid formed with a knife in the places they 
now occupy. The design is carefully drawn on the bar, 
and the work begins by making a diagonal cut across 
each corner for the corner posts, not cutting through 
the floors of the different stories. Then the inner 
postern is cut roughly in the form of a cylinder. The 
cross cuts are then made and the pieces are shaped into 
balls. The spindle in the lower story is formed in the 
same w^ay, but it is cut loose by running the point of 
the knife into the apexes of the cones formed above 
and below^ the spheroid, thus at one operation forming 
the points of the spindle and the bearings for them. 
The posts at the corners are left as large as possible 
and finished finally by taking off only enough w^ood to 
make them straight and square. 

An anchor with its cross bar and ring is made of a 
single piece of wood a little thicker than the width of 



HOME MECHANICS FOR AMATEUKS 21 

the flukes. The cross bar is whittled out parallel with 
the shank of the anchor, and the curved end is cut 
across the "rain. The hole in the shank is formed at 
the same time the curved end is cut loose. The shoulder 
on the bar is thus formed and the bar is pushed through 
the hole in the shank. A small mortise is made in the 
bar to receive the key which keeps it in place. The ring 
at the top of the anchor is made in the same manner as 
the first link of the chain. The anchor looks very sim- 
ple, but it is in reality quite difficult. 

In all these examples the wood should not be cut 
away more than is necessary, except to finish. 

The puzzle shown assembled and separated cannot 
readily be described. The pieces are notched so that 
they will go together and form the symmetrical whole, 
as shown in the engraving. 

DIFFERENT SHAPES OF SAW TEETH AND THE 
WAY THEY CUT* 

The accompanying sketches show the different shapes 
of saw teeth and the way that they cut the timber. Fig. 
16 shows the dress of a shingle saw tooth. By examin- 

\\\W -/////////////A -wwwwVwVWW ' 

Pig. 16. The " Dress " of a Shingle Saw Tooth. 

ing it, it will be seen that it is a ^'sprung tooth," and 
the teeth cut on alternate sides of kerf, taking two teeth 
to clear out the kerf on both sides. The bevel of the 
teeth gives it a shear cut on the timber. The Avood will 
slip on the edge of the teeth, wearing them on the inside 
and leaving the outer corner full and sharp, and a cor- 
* From the Saw Mill Gazette. 



22 



HOME MECHANICS FOR AMATEFRS 



ner to clear up the side of the kerf, thus making smootli 
lumber. 

Fig. IT shows a square dressed tooth. The wood 




Fig. 17. A Square 
Dressed Tooth. 



Fig. 18. 
A Vertical Saw with Square Teeth. 



wears off the corners, leaving them dull, and they will 
fly from timber to the other side if the wood is not 
equal in hardness, and lead the saw to that side of the 
log. This trouble is found in wood with a hard and 
soft grain or in knots, but with the beveled teeth the 
sharp corner will lead the saw straight. 

Fig. 18 shows a vertical saw with square teeth, a very 
common dress. The wood wears the out corner off, 
leaving it round or blunt, and as there is nothing to sup- 
port the inside of the teeth, they will fly from the wood. 




Fig. 19. A Swaged Tooth of the Same Kind as Fig. 18. 

and in the up stroke of the saw wear against the side of 
the kerf until w^orn in the shape shown in cut. 

Fig. 19 is a swaged tooth of the same kind of saw and 
is a ver}^ good dress for sash, muley, gang, and other 



HOME MECHAXICS FOR AMATEURS 



23 



saws nsiii<j; li.i>ht fet'd, but for heavy feed it is better to 
swage the teeth out on both sides and joint off for set. 
By referring to Fig. 20 it is seen that all teeth of this 
shape cut with a scrape cut, not with edge cutting, like 




a chisel, but with the edge set at right angle with the 
line of cut. For soft w^ood, such as white pine, ham- 
mer the top of the teeth, turning the edge down enough 
to give a cutting edge downward. Figs. 21 and 22 are 
circular log saws. 

Fig. 21 shows a side view of a tooth. It is seen that 
the back of the tooth lies close to the wood, and the 




Fig. 21. Side View of Circular Saw Tooth. 



tooth may be filed thin without danger of breaking. 
This dress of saws cut Avith a chisel cut, will carry more 
feed than any other, and at the same time do the best of 
work. 



u 



HOME MECHANICS FOE AMATEURS 



Fig. 22 shows the shape of the edge of the same tooth. 
It being hollow on the edge, with the corners sharp, 
the wood will fiv or slip from the corners, not wearing 
them as much as a square tooth, leaving a good corner 





"iiiiii ^ 

Fig. 22. 
Edge of Circular Saw Tooth. 



Fig. 23. 
A Square Dressed Tooth. 



to clear the sides of the kerf. It will be seen by refer- 
ring to Fig. 22 that it takes two teeth, one on each 
side of the saw, to cut both sides of kerf, but in this 
dress each tooth cuts both sides, and again, if a beveled 
sprung tooth is forced to do more than a medium 
amount of duty, it will fly into the wood and be in dan- 
ger of tearing off the teeth. 

In Fig. 23 is seen a square dressed tooth. All teeth 
swaged with a square dress leave the corners rather 
weak and not much to joint off the side in setting. 
This shows one such tooth cutting through cross 
grained or twisted timber, a sharp corner but nothing 
to clear the side of the kerf, the cross grain filling so 
much of the kerf as to rub on the plate of the saw and 
heat it. 



HOME MECHANICS FOR AMATEUKS 25 

Fig. 24 refers to a dress for hand and other saws that 

Fig. 24. Dress for Hand and other Saws, 

is nsed for cross-cutting soft wood that is to be cut very 
smooth. 

A WRINKLE IN SAWING 

A try-square is not always at hand when it is desired 
to saw a sticlc, and when it is handy some mechanics 
prefer to work by ^^guess" than otherwise. When a 
bright straight saw is placed upon a stick or on the edge 




Fig. 25. Reflection Substituted for the Try Square. 

of a board, the reflection of the stick or board in the 
saw is sufficiently well defined to permit of placing the 
saw so that the reflected image coincides with the object 
reflected, forming a continuous straight line. If the 
sawing is done while the image and the stick are in line, 
the stick Avill be cut at right angles. 

It is obvious that a line may be drawn at right angles 
to the stick by arranging the saw as shown in Fig. 26. 
If, after forming this line, the saw be placed across the 
stick so that the line and its reflected image and the 



26 HOME MECHANICS FOE AMATEUES 

stick and its reflected image form a square, with the 
reflected image and the stick lying in the same plane, 




Fig. 26. Laying out Work by Reflection. 




Fig. 27. Forty-five Degree Angle by Reflection. 

as shown in Fig. 27, the stick ma}^ be sawed at an angle 
of forty-five degrees, provided the saw is held in the 
same position relative to the stick. 



WOOD CARVING 

To one having an idea of form and proportion, wood 
carving is not very diflflcult, even though a practical 
knowledge of drawing and modeling be wanting. Cre^d- 



Tro:\rE imechaxtcs for A]\rATETTES 2: 

i table specimeus of carving have heeii |)r()(lneed bv 
means of the pocket knife alone, by persons having 
dextrous hands and good eyes; but it takes a good 
workman to produce a fine job with poor tools, or none 
at all, therefore the average wood carver will be obliged 
to rely somewhat upon tools and appliances. In fact, 
the more complete the set of tools and the more perfect 
the accessories, the more readily can the work be done 
and the more satisfactory the result. 




Fig. 28. Violet Panel. 

The principal tools are gouges, chisels, parting tools, 
curA'ed and straight, a heavy mallet, a light mallet, a 
solid bench, and some clamps. As to materials: For 
the beginner soft woods are best, such as pine. Avhite 
wood, or cedar. After a little experience, pear, black 
Avalnut, and oak may be tried. Nine-tenths of the dif- 
ficulty in carving is in working one's self up to the 



28 



HOME MECHANICS FOR AMATEUES 



point of setting out in the work. The chances are that 
in the beginning the tyro wiU not succeed in producing 
the exact forms desired; but progress will be made with 
every successive trial. 

It is, indeed, difficult to give any explicit directions 
for carving. We might almost say, here are the ma- 
terials, the tools, and the design. The whole of carving 
is to take these tools and cut this design from this piece 
of material, using your own judgment, at the same 
time "making haste slowly." 




Fig. 29. Carvirxg Tools. 






Fig. 30. 

Edge View 

of Tools. 



The tools required are shown in Fig. 29, 1 being a 
firmer, 2 a straight gouge, 3 a curved gouge, 4 a bent 
chisel, 5 a front-bent gouge, 6 a back-bent gouge, 7 a 
parting tool, 8 a curved parting tool, and 9 a macaroni 
tool. These tools can be purchased either separately 
or in sets. There are other forms and many different 



HOME MECHAXICS FOE AMATEURS 29 

sizes. It is well to begin with a half dozen medinin 
sized tools, and then learn by experience what further 
tools are required. A flat and curved chisel and a flat 
and curved gouge, each one-half inch wide, a narrow 
deep gouge, and a parting tool are sufficient for the 
first effort. 

The design is marked upon the wood to be carved, 
and the outline is shaped by means of a scroll saw, if 
the design is to be in high relief, and the most promi- 
nent is isolated from the rest. Avoid cutting too 
deeply, or raising slivers that run into the wood and 
spoil the work. Where the carving is done on a flat 
surface in low relief, gouges having little curvature 
are required. 

The tools should be kept as sharp as possible, to se- 
cure smooth work and to economize labor. Carving 
tools are usually sharpened from both sides by means 
of suitable oil stone slips and by leather strops charged 
with crocus. 

The wood while being carved is held in place on the 
bench by means of screw clamjjs, or by pointed screws 
passing upward through the bench into the back of 
the work. 

In Fig. 28 is shown a panel of violets, which may be 
copied after some experience is gained. It is easier, 
however, to copy other carvings than to produce the 
work from engravings. 

Simple subjects should be chosen, and no work 
should be passed until it has been made as perfect as 
the tools, materials, and ability of the carver will per- 
mit. A final finish imparted with tine sandpaper is ad- 
missible ; but neither sandpaper nor putty should be de- 
pended upon as material aids in this kind of work. 



PART II. 

hoay to make household 
or^^ame:n^ts 

home made grilles and gratings 

A DWELLING HOUSE without ornamentation 
of the class mentioned above indicates one of 
three things — either the owner or occupant 
does not appreciate the value of this kind of 
home decoration or he does not possess the skill to 
make or the power to purchase it. It is true, the 
beautiful metal and wood work now manufactured for 
this purpose is very expensive; but it is also true that 
something equally as beautiful may be had without 
much trouble or expense. 

The grilles shown in Figs. 31, 32, and 33 are made of 
rope, sized, bent into shape, dried, glued in a wooden 
frame and finally painted an appropriate color or 
gilded or bronzed. These ornaments when placed in a 
doorway or w indow or across a hall from the stairway 
to the wall, or in some corner in the library, add won- 
derfully to the appearance of the room. 

The materials required are some iV inch sash cord, 
glue, round sticks or doweling t\ inch in diameter, 
paraffine (a paraffine candle will do), some strips of 
wood, and paint or varnish. 

There are in the present case only two fundamental 
forms for the spindles or bars, but these are combined 
in several different ways, as shown in Fig 36. The spin- 

[31] 



'62 



HOME MECHANICS FOR AMATEURS 



die most used is sliOAvn in Fig. 34. It is formed by 
winding- the sash cord — which has been previously 
steeped in the glue size — upon the wooden rod. The 
rod is coated with melted paraffine before use, to pre- 
vent the size from adhering, and equidistant marks are 
made upon the rod as guides for the winding. These 
marks are 1^ inches apart. The winding can be easily 
done by placing one end of the wooden rod in a vise, 
driving a tack through the end of the rope into the rod. 
If every turn of the rope around the rod is made to co- 
incide Avith one of the marks, the spindle will be true 
enough for all purposes. A tack should be driven 




Fig. 31. Grille for Double Doors. 



through the end of the finished spiral into the rod to 
prevent the rope from unwinding. A number of rods 
will be required. Part of the spindles should be wound 
in a right-handed direction and the remainder in a 
left-handed direction. The rope should be allowed 
to stand for a day or so to dry. It is well, espe- 
cially in warm weather, to add to the size some oil of 
cloves or carbolic acid to prevent it from souring while 
drying. 

The other form of spindle is shown in Fig. 35. This 
is made by bending the sized rope around pins driven 
into a board in two rows, the pins of one row alternat- 



HOME MECHANICS FOE AMATEURS 33 




Fig. 32. Rope Grille for Window, Door, or Hall. 

ing* in position with those of the other row. The board 

and pins are covered with paraffine, as in the other case. 

The spiral spindles may be combined with each 

other, as shown at a^ h, c, d, and e in Fig. 36, and with 




Fig. 33. Grille for Window. 



34 



HOME MECHANICS FOR AMATEURS 



a straight rod, as shown at /. At g they are shown in 
combination with the zigzag rope. At // the zigzag rope 
is shoAvn in combination with straight rods. 

The circles and segments of circles shown in Figs. 32 
and 33 are made by winding the sized rope around a tin 
pail, a can, or some other cylindrical body and allowing 
it to dry. To form a complete ring, one turn of the rope 
is cut off, its ends are cut off diagonally and fastened 
together with strong glue. 

The spindles are cut by means of a sharp knife. The 
various parts of the work are fastened together and at- 
tached to a light wooden frame, and, as a rule, no fas- 
tening other than glue w^ill be required. If, however, a 
stronger fastening is necessary at some points, small 
brads or wire nails, or even screws, may be used. 

In Fig. 33, the rosette, d^ is formed of a circular ring 
filled with segments of a similar ring in the manner 
shown. Each pair of spirals, a, consists of one right- 




PiG. 35. Zigzag Bar, 



handed one and one left-handed. The spindles, h, c, 
are spirals. 

Grilles made in this way may be finished in the same 



HOME MECHANICS FOE AMATEUKS 



35 



manner as wood. They may be stained or painted to 
matcli the work into which tliey are fitted, or they may 
l)e painted white and relieved by a little gilt on the pro- 
jecting part. 

It is obvions that a large nnmber of patterns may be 
Avorked ont by the aid of these suggestions. Different 

Oy Jf e^ d. e J *9 y^- 




Fig. 36. Forms of Spindles and Bars. 

kinds and sizes of rope may be used alone or in combi- 
nation. 

Tliese grilles may be placed in windows, doorways, 
across halls, above mantels, across niches, between win- 
dows, and in many other places which will suggest 
themselves. Like many other household ornaments, if 
well and carefully made, they will repay the labor and 
trouble of makinj?. 



WALL ORNAMENTS 

There is a great deal of satisfaction in the possession 
of home made ornamental objects, because they are the 
work of one's own hand, and, besides this, they are not 
obtained by the expenditure of money that might per- 
haps, be needed for other purposes. 

Ornaments belonging to the wall go a long way in 
furnishing and beautifying the house. Pictures, care- 



36 



HOME MECHAXICS FOR AMATEURS 



fully selected, are liiglih^ effective. ^lauy of the mod- 
ern photographs, photo-graviires, and photo-engravings 
which are really meritorious can be obtained for fifty 
cents or a dollar each. Some fairly good etchings and 
imitations of water colors are also sold at reasonable 
prices. The great item in connection with a low-priced 
picture is the frame ; but any one Avith such tools as are 
commonly found about the house and Avith a small 
quantity of material can readily make a variety of 
frames worthy of any place in the house. 

The simplest frame to make is that shown in Fig 37. 
This is made from a narrow flat board of chestnut, 







Fig. 37. Wooden Frame. 



butternut, or even ash or oak, having its inner edge 
rabbeted to receive the glass, mat, and backing. This 
strip is stained and finished before it is mitered. The 
staining is done by brushing the strip evenly with a 
thin coating of asphaltum, or with a thin stain of log- 



HOME MECHANICS FOR AMATEURS 3*? 

Avood, or witli a stain foniuMl of (^ither of the following 
dry pigments, bnrnt nniber, bnrnt or raw sienna, mixed 
witli turpentine and a very small proportion of boiled 
linseed oil. Chemical ink or writing fluid, reduced 
with water so as to produce a greenish gray tint, 
answers a good purpose. 

After the stain is dry, the tint is lightened along the 
inner or outer edge of the strip, as taste may dictate, 
l)y scraping the wood by means of an ordinary wood 
scraper, or by rubbing the surface down by means of 
fine sandpaper. It is obvious that the stain may be 
applied to the wood in such a way as to graduate the 
tint without the necessity of scraping or sandpapering, 
but this requires practice. 

The tint should be so graduated as to be very light, 
or nearly the natural color of the Avood at one edge of 
the strip, Avhile the other edge should be quite dark. 
The strip may be finished by flowing over it three thin 
coats of shellac a arnish, allowing each coat to dry thor- 
oughly before applying the next. The first tAVO coats 
should be rubbed doAvn with very fine emery paper 
after they become thoroughly dry and hard. The last 
coat ma}^ be left bright, or its luster may be toned 
down by means of the fine emery paper. The mould- 
ing or strip thus prepared is mitered in the usual Avay 
by the aid of a miter box, and nailed and glued to- 
gether at the corners. 

The mat in this case consists of a piece of thick paste- 
board in Avhicli is cut an opening of the desired form. 
The edges of the pasteboard are beveled around the 
opening, and cauA^as, crash tOAveling, or AAiiite or tinted 
cotton velvet is secured to the pasteboard by means 
of bookbinder's paste (flour paste \Aath glue added). 



38 



HO]\[E MP:CHAXICS foe AMATErRS 



Afttir the paste bcccjiues dry, if desired, a design may 
be painted on the mat with water colors. 

The frame shoAvn in Fig. 38 is made on a different 
plan. In this case the wooden moulding is half round 
on its face. A saw kerf is made at the inner side of the 
rabbet. The edge of a strip of white or ^^ivory'' zylon- 
ite is inserted in the saw kerf, and held there by a thin 




Fig. 38. Zylonite Frame. 



strip of wood glued in. A small percentage of glycer- 
ine or even common molasses should be added to the 
glue used for this purpose. The zylonite is wrapped 
around the moulding and fastened by means of a thin 
strip of wood laid over it and secured by small nails or 
brads. The corners of this frame are formed by means 
of rectangular blocks of wood painted white on their 
sides and furnished on the front with a square of zylon- 
ite held in place by an ornamental brass nail. 

If a larger frame is required, that can be made with 



HO:\lE MECHANICS FOR AMATEURS 



39 



a single strip of zylonite, the joint may be covered by 
means of a curved half round strip of brass well pol- 
ished and lacquered, and applied as shown in the en- 
graving. 

This frame may have a gilt lining as well as the mat. 
It has a very chaste appearance, looking much like a 
frame of ivory, and it is withal durable. 




Fig. 39. Feather Ornament. 

A very pretty and easily made Avail ornament is 
shown in Fig. 39. It consists of a number of peacock 
feathers arranged radially or in the form of a fan with 
the quills attached to an elliptical piece of pasteboard 
by means of sealing wax. The pasteboard is fitted to 
an iridescent shell and fastened in with sealing wax. 
A wire loop inserted in the pasteboard serves for hang- 
ing the ornament. It may be placed between windows, 



40 



HOME MECHANICS EOE AMATEUES 



above or below pictures, and in man^^ other places with 
good effect. 

In Fig. 40 is shown a wall cabinet, which is not only 
highly ornamental, but very useful. The body of the 
cabinet is of pine or other soft wood. The doors are 




Fig. 40. A Wall Cabinet. 



arranged to receive the beautiful zylonite bas-reliefs 
sold by the manufacturers of this superb material. In 
openings in the back of the cabinet are inserted orna- 
ments of the same character. They resemble ivory 
and are very serviceable. 

The bod}^ of the cabinet is neatly covered with can- 



HO]\rE MECHANICS FOR AMATEURS 



41 



vas, toweliiii»", or lii;litlv tinted cotton velvet, on wliicli 
are painted designs in water or oil colors. The edges 
of the shelves are preferably covered with sheet zylon- 
ite, although they may with good effect be covered with 
the material used on the other parts of the cabinet. Or- 
namental brass hinges and trimmings should be applied 
to the doors, as shown in the engraving. 



PSEUDO-CERAMICS 

The ceramic art is generally practiced under condi- 
tions which render it exceedingly difficult for an ama- 






fpi^i . ■ 



■■'^^WM 





Fig. 41, Square Vase. 



teur to make progress in it, even so far as to produce 
work of the most modest and unassuming character. 



42 HOME MECHANICS FOE AMATEURS 

lu the first plac(^ it is difficult to obtain the proper 
quaHty of clay, unless one is in the yicinitj of a pottery 
or clay bed ; in the second place, even though one has 
the skill and practice which will enable him to shape 
the clay into the desired forms, still it is difficult, if not 
impossible to bake the work after it is done in other 
respects, and it can scarcely be expected that a potter 
will bake these odd articles. These and other difflcul- 



M 










j^ ~^^ 






Fig. 42. Triangular Vase. 

ties prevent the would-be amateur potter from attempt- 
ing what, under more favorable circumstances, might 
be productive of works creditable to both the art and 
the artisan. 

Eecently some exceedingly plain articles of pottery, 
with extremely simple ornamentation, consisting 
merely of a little paint and a little glaze, have become 
very fashionable, and have been accepted as works of 



HOME MECHAA1C8 FOK AMATEUKS 



43 



art. Some of tliese articles are handsome, others are 
not. Inasmuch as these articles have no practical 
utility, they do not require to be made of materials 
either fireproof or waterproof. The requisites are 
simply shape, strength, and a resemblance to pottery. 
The materials required for making imitation pottery 
are junk-board — a strong, thick board having a smooth 
surface — glue, and small wire nails. The ornamenta- 
tion may consist of such floral or landscape decorations 
as the maker is able to produce if he or she be artist 



"^"T 



^::^; 



§0: m^smiM 




Fig. 43. Cylindrical Vase. 

enough to paint in oil colors. Without this ability the 
aid of chromos must be invoked. This will certainly 
afford very satisfactory results, and the expense will b(* 
slight, as very passable German chromos may be ob- 
tained for twenty-five cents each. The engravings show 
several examples of pseudo-ceramics Avhich are de- 
signed with reference to the material to be employed, 
and compare favorably with the high-priced articles to 
be found in the shops. 



44 HO^rE MECHAXICS FOE AMATEUES 

Tlie body of tlic vase shown in Fii*. 41 consists of 
rectangular pieces of jnnk-board nailed and glned to- 
gether at the corners, after the fashion of an ordinary 
wooden box. The nails used are the small wire nails 
used in bracket-work. They are about three-eighths 
of an inch long, and about the size of an ordinary pin. 





Fig. 44. Vase with Latticed Base. 

In the absence of such nails common pins may be cut off 
and used to good advantage. Holes for these nails 
must be made with a fine-pointed awl. The bottom of 
the vase consists of a single piece of junk-board, with 
V-shaped notches cut from the corners to give it the 
bevel. 

The concave sides of the top consist of sections of 



HOME MECHAXICS FOll AMATEUES 



45 



paper tube such as is employed for inailin.u pictures. 
The bead around the top is of Avood. Any imperfec- 
tions in tlie joints may be filled with a mixture of glue 
size and whiting formed into a putty. 

Fig. 42 sho\ys a yase which can readily be made after 
the aboAX^ hints. It is triangular in form, and has three 
Ayooden balls for legs. The band around the top is 
merely a narrow strip of pasteboard glued on. 

Fig. 43 shows a cylindrical yase made of a strip of 
junk-board scarfed or beyehMl on the edges and lapped 




Fig. 45. Elliptical Vase. 
and glued. To facilitate bending the junk-board, the 
side which is to be outermost in the yase is wet. The 
bottom is glued and nailed in, and the corners are 
rounded with a moderately coarse file and sandpaper. 
A band of pasteboard finishes the top, and three or four 
wooden balls form the legs. The inner corner of this 
yase at the bottom may be filled in slightly Avitli glue 
and Ayhiting to strenii'then it. 



46 



HOME MECHANICS FOR AMATEUES 



The vase shown in Fig. 44 is made in the same way 
as that last described. The bottom is placed above the 
lattice work. The latter is formed by cutting out the 
holes Avith a chisel. The ring and its fixture are made 
of wood. 

Figs. 45, 46, and 47 are examples of "pilgrim" vases 
of different shapes. That shown in Fig. 47 is circular, 
and has convex sides or heads. The hoop is bent in the 
manner already described, i. c, after first wetting the 




Fig. 46. " Pilgrim " Vase. 



outer side. The heads are made convex by wetting the 
junk-board and hammering it in the middle, in the same 
Avay that a shoemaker hammers a shoe sole, or tap, to 
nmke it convex, that is, it is placed upon an ordinary 
fiat-iron or sad-iron, and hammered with a round-faced 
hammer until it acquires the desired convexity. The 
sides are nailed and glued to the hoop, and a thin paste- 
board circle is glued to each of the convex surfaces of 
the vase to form a border. The mouth of the vase is 



HOME MECHANICS FOR A.MATEURS 



47 



made of four pieces of junk-board, glued and nailed to- 
o-etber and secured to tbe vase bv olue. Tbe legs of tbis 
vase consist of two pieces of paper tube closed at tbe 
ends witb turned pieces of wood. Tbe corners of tbe 
vase may be filed and sandpapered to make it ready for 
furtber operations. 

After wbat bas already been said tbe construction of 
tbe vases sbown in Figs. 45 and 46 will need no descrip- 




o ?■" " , ' 



ij 



Fig. 47. Circular Vase 





tion, except tbat tbe vase sbown in Fig. 46 bas wooden 
legs and wooden strips at tbe sides of tbe moutb. 

Tbe body of tbe vase sbown in Fig. 48 can be con- 
structed witbout special description. Tbe ornamenta- 
tion consists of ordinary artificial flowers and vines, se- 
cured to tbe body of tbe vase witb common glue. Tbey 
are stiffened by spraying or spattering sbellac var- 
nisb on tbem from an old tootb or nail brusb. Tbey 



48 



HOME MECHANICS FOR AMATEURS 



should be sprayed several times to give tlieiii a good 
heavy coating of varnish. When this becomes dry the 
leaves and tiowers may be painted in the same manner 
as the other parts of the vase. These vases should be 
smoothly finished and thoroughly dried before any at- 
tempt at finishing is made. The first operation in the 
way of finishing is to give the vase two coats of shellac 

, -- _ -^--. varnish inside and out, 

allowing one coat to be- 
come dry before the 
other is applied. When 
both coats of varnish are 
dry and hard, which will 
require about two days, 
the painting may be 
done. 

It is not the design of 
this section to enter into 
all of the details of 
painting necessary to 
enable the tjvo to paint 
landscapes or flowers, 
but a suggestion or two 
in regard to the paint- 
ing will not be out of 
place. The best results 
will be obtained by giv- 
ing the vase two coats of white paint before attempting 
to lay on the color. The sides and border of the vase 
should be of a neutral tint, slightly mottled. An olive 
green or a gray looks well and gives relief to any de- 
sign that may be chosen. 

No attempt should be made to apply the colors 




Fig. 48. Vase with Leaves 
and Flowers in Relief. 



HOME MECHAXICS FOE AMATEUliS 49 

sniootlily. The whole sliould be done in a bold, dashini^ 

If paintin<>- is out of the (]uestion, some of the chro- 
nios before mentioned may be nsed with i;ood effect. 
The edges of the ehromos may be concealed beneath the 
pasteboard border. In either case after the paint on 
the article has become thoronghly dry and hard, which 
will probably reipiire fonr or six weeks, it may receive 
a coat of pottery varnish, to be obtained at any of the 
color stores. 

In the case of the applied artiticial flowers, they 
shonld be hea\dly painted with, sa}^ four or five coats of 
white paint before applying the color. 

Ornamental articles of this kind cost little save the 
labor, and will well repay the trouble of making. 



IMITATION OF MAJOLICA 

Cements and sealing wax are nsefnl for giving to 
paper and wooden articles a hard glaze, resembling that 
of majolica ware. The cylindrical vase shown in the 
following engraving consists of a paper mailing tube 
3 inches in diameter, and 6 inches long, furnished 
with a pasteboard bottom, which is glued in. The 
inside and bottom of the vase are provided with two or 
three coats of asphaltum or shellac varnish to render 
it waterproof. The outside is covered with jeweler's 
cement of different colors, or with sealing wax, or 
both. The bar of cement or wax is melted at the end, 
and applied to the paper cylinder in the same manner 
as it is applied in sealing packages. No particular care 
is required in applying the wax. It is, however, neces- 
sary that the edges of adjoining patches of wax be 



50 



HOME MECHANICS FOR AMATEUKS 



broiiglit into contact with each other to insure the com- 
plete covering of the paper. In the example shoAvn in 
the engraAing, olive green jeweler's cement forms the 
covering of the lower part of the vase. This is blended 
into cement colored with Venetian red or Indian red, 
and the cement at the top is flecked with yellow. 

The mass of cement is laid on in spiral lines, and 
when the covering is complete, the vase is held over a 

smokeless flame, such as 
that of a Bunsen burner 
or alcohol lamp, or it 
mav be held over a coal 
fire until the cement 
fuses. The vase should 
be turned in such a way 
as to cause the variously 
colored cements to run 
into each other. The 
vase is held by means of 
a paper tube or a stick 
inserted in its open end. 
Ornamentation may be 
applied by cutting 
leaves, stems, petals, 
etc., from pieces of thick 
paper, dipping them in 
melted cement of appro- 
priate color, allowing 
them to cool, afterward 
arranging them upon the vase; finally softening the 
cement of the vase and the ornament by holding a flame 
or a hot iron over them until the cement softens, and 
the ornaments are attached. Care is required at this 




Fig. 49. Imitation of Majolica. 



HOME MECHxVXICS FOR AMATEUES 51 

point to avoid the complete fusing of the cement, as 
this Avonld spoil the job. Care is also required to 
avoid igniting tlie cement or wax, as it is nearly impos- 
sible to extinguish it. 

STAINED GLASS AND OBJECTS OF WIRE 
CLOTH 

A little stained glass work judiciously distributed 
imparts a bright and cheerful air to the house by intro- 
ducing a few brilliant colors in a legitimate way, where 
they would be entirel}^ out of place if introduced in 
draperies, carpets, or furniture. 

It is an easy matter to make stained glass work after 
the more simple designs. It only requires a knowledge 
of the use of the glazier's diamond, or the very effi'-ient 

^ It -^ 




L 
Fig. 50. Details of the Lead Work. 

substitute for the same known as the roller glass cut- 
ter, and some proficiency in the use of the soldering 
iron. 

The colored glass can be procured from almost any 
dealer, and for the grooved lead strips in which the 
glass is set, the amateur will have to depend on the 
stained glass Avorks. Some manufacturers are willing 



52 HOME MECHAXICS FOE AMATEURS 

to furnish it in small quantities, while others are reluc- 
tant. It is to be regretted that there is no simple way 
of making these strips. Every stained glass manufac- 
turer is provided with a machine by means of which he 
rolls them from larger strips of about the same form, 
made at the lead works, and known as cames. 




Fig. 51. Stained Glass Work " Crazy " Pattern. 

Two kinds of lead strips are generally used in this 
kind of work, one of Avhich is shown at r/, in Fig. 50. 
This is narrow and convex, and well adapted for small 
curves, circles, etc. The other, shown at h, in the same 
figure, is wider and thinner and better adapted for 
straight Avork. At c, in the same figure, is shoAvn the 
method of attaching copper Avires to the lead for twist- 
ing around the rods which support the work, as shown 
at^. 

A drawing of the pattern is made upon stout paper, 



HOME :\rECHAXICS FOE AMATEUES 53 

iuid the work is bei^uii hv enttim>- tlie olass accordiuir 
to tlie pattern, fittiiio- the lead strips and soldering* 
them at their jnnction. After all of the glass pieces 
have b(Mm fitted and secnred, the work is tnrned over 
and soldered upon the other side. The wii'( s are then 
attached by first tinning them and then secnring them 
by means of soldia'. These wires are twisted around 




Fi(i. 52. A Leaded Glass Butterfly. 

iron rods, which are so arranged as to support the work. 
Small pieces Avill not require the iron rods, but larger 
ones are liable to sag and buckle of their own weight. 
They are also apt to b(^ blown out of shape by a heavy 
wind. The easiest pattern to produce on stained glass 
is that shoAvn in Fig. 51. It is hardly worthy of classi- 

* P'or the soldering, an ordinary soldering iron is employed, and 
common tinner's solder is used in fastening the joints. Tallow is 
used as flux. A tallow candle is commonly employed for this pur- 
pose. The joint to be soldered is rubbed with the end of the 
candle, and the solder is applied. Of course the iron must be well 
tinned and hot, and the touch of the iron upon the work must be 
very quickly and dexterously done. 



54 HOME MEC'HAXICS FOK AMATEUES 

fication among patterns, bUt it is pleasing if properiy 
(lone. Some care is necessary to secure harmony of 
color, but there is little chance of failure in this kind of 
Ayork. 

It is a common practice to gild oyer the lead strips 
after the work is done, by means of gold paint, but it is 
a question whether it is any improyement oyer the nat- 
ural color of the lead, especially in work exposed to the 
action of the elements. For some indoor work, such 
as fire screens, sash screens, lanterns, lamp shades, etc. 
the gilding is not objectionable. 

The screen shown in Fig. 52 is not difficult. All of 
the glass pieces are of such form as to be easily cut, and 
the work of joining the lead str-ips is quite simple. As 
to colors, it would be well to follow the example of na- 
ture, or in any case to select such as will harmonize. It 
is hardly possible to produce more gorgeous coloring 
than is found among the butterflies. Green, blue, 
greenish-blue, red, yellow, brown, black and white 
(opalescent^ are colors from which to select for this 
object. 

The wire frame which supports the glass is carried 
along the lead strips and secured by solder. The an- 
tennae are of wire. The base is of wood, neatly stained 
and polished. 

A class of ornamental objects may be made from wire 
cloth which riyal in beauty any kind of stained glass 
work. Figs. 53 and 54 are examples of this kind of 
work. 

The wire cloth for this puri3ose should be made of 
fine wire, the mesh should be coarse, say 10 to the inch, 
and, moreoyer, the cloth should be painted and allowed 
to dry before the ornamental work is applied. The 



IIO.AIE MECHANICS FOli AMATEURS 



55 



wire cloth is supported a short distance from a design 
drawn on paper and the different colors are introduced 
into the meshes by means of an ordinary writing pen. 
A gelatine solution is used for this purpose. It should 
not be very thick, and it must be kept warm. Ordi- 
nary, transparent gelatine may be colored for this pur- 
pose by adding aniline. Colored lacquers answer ad- 





FiG. 53. Lamp Shade. 



Fig, 54. Hanging Lantern 
of Wire Cloth. 



mirably for filling the squares. Common white glue 
answers very well for filling the body of the design. 
The beauty of this kind of work and the simplicity of 
the method by which it is produced recommend it for 
many purposes. 

The construction of the frames for the lamp shade 
and hanging lantern requires some mechanical skill. 



56 



HOME :\rECHANlCS FOR A:\rATEUES 



Trobablv the aid of the tinsiiiitli will have to be in- 
voked in these cases. It will pay, however, as the arti- 
cles will well repay the trouble and expense. 

The hanging lantern, h'ig. 54, is designed for a hall. 
It may contain a kerosene lamp, or the device known 
as the ''fairy lamp,'- in which a large candle is em- 
ployed as a source of light. 

The colored checks in the wire cloth appear like gems 
when illuminated. 

An experiment showing a phase of capillarity is illus- 
trated b}^ the annexed engravings, which give patterns. 



-- 


S 




^Hil 




X A V 














1' \ 


llT-=t 


nil H^ 1 


\\ 




' ' \ 


X iu 




:::l 


-i^-i 






r-%=== 


-j-l- J 




11 


*-i'- 




-■^--1 


■-}, 




; i 


■ 


fcL-. 


■gj-^p^it- 


~™"l| 1 


■L 






— - 








i.:'- 


ii':-fc 


T- - 1 


:- 


ii:: 


E::^." 


p 1 


I 


■F ■?-:::_ 


i--|l 


f::: = :!Bffin"F 


-■---| 


t 






"'' 1 







^^ 




|t:::T[:;:: 

r - : : : 1 it j^ 


1 




-:S'--ll' "; 




Kl 


lfe 





Fig. 55. Method of producing Designs on Wire Cloth. 



This experiment was originally intended for illus- 
trating tapestry and other designs formed of small 
squares, in colors, upon the screen ; but it has another 
practical application, which is capable of considerable 
expansion. For projection, a piece of brass wire cloth, 
of any desired mesh, say from 12 to 20 to the inch, 
is mounted in a metallic frame to adapt it to the slide 
holder of the lantern, and the wire cloth is coated 
lightly Avith lacquer and allowed to dry. 

The slide thus j)repared is placed in the lantern and 
focused. The required design may now be traced by 



IT():\rE MECHAXTCS FOE A:\rATKrEi^ 57 

nieaus of a small caiiicrs hair bnisli, colored inks or 
aqueous solutions of auiliue dyes Ijeinii- used. The 
snuill squares of the wire cloth are filled with the col- 
ored liquid, and show as colored S(]uares upon the 
screen. Different colors may be placed in juxtaposi- 
tion without liability to mixing-, and a design traced 
without special care will appear regular as the rec- 
tangular apertures of the wire cloth control the differ- 
ent parts of the design. 

The colored liquid squares are retained in the meshes 
of the wire cloth by capillarity. A damp sponge will 
remove the color, so that the experiment may be re- 
peated as often as desired. In this experiment the 
colored squares have the appearance of gems. 

These designs nuiy be made permanent by employ- 
ing solutions of colored gelatine; but in this case the 
squares are so small that they are not very effective 
without magnification. Really elegant designs may be 
produced in this way for lamp shades, window and fire 
screens, siuns, etc., as described above. 



JAPANESE PORTIERE OR CURTAIX 

There is a certain delicacy in a curtain macte of 
long lashes formed of straw or bamboo and beads 
which is not found in a fabric of any kind. Cur- 
tains of this sort have been largely introduced into 
this country of late, some of them being simple, plain 
and cheap, while others are really very elaborate and, 
of course, correspondingly expensive. It is a very 
simple matter to make a curtain of this class, pro- 
vided the materials are at hand ; but where neither 
bamboo nor straw nor beads are available, it becomes 



58 



HOME MECHANICS FOR AMATEURS 



more difficult. But a very presentable curtain may 
be made from paper, Avhich is obtainable everywhere. 
The large engraving sIioavs a very simple pattern 
made of straws of different length, and glass beads 
of different colors, strung on strong thread or fine 
strong twine. 

The first thing to be done toward making the cur- 
tain is to draw a design roughly on a sheet of paper, 
then tie a thread in a bead Avhich is to form the fin- 
ish of the lower end of the lash. Then the bead is 




Fig. 56. Method for making Paper Rolls. 



fastened in its place on the pattern by driving an 
ordinary pin through it into the board or table be- 
neath. The stringing of the straws and beads is thus 
proceeded with according to the requirements of the 
pattern. 

When one lash is finished, its upper end is fastened 
on the design by an ordinar^^ jun driven through a 
knot tied in the thread. The next lash in order is pro- 
ceeded with in the same manner, and so on until the 
entire series of lashes is done. A stout string is 



BCniK ^rKdlAXTCS FOIJ A:\rATFJ^T7S 50 

stretched along the series of pins by which ilie upper 
ends of the laslies are secured. Eacli thread is tlien 
tied around the transvere string. If desired, the threads 
may be spaced by beads arranged on tlie string be- 
tween the lashes. As all the knots are necessarily 
trimmed close, it is well to touch each knot with muci- 
lage. When this is dry, the curtain is finished. 

A very handsome curtain may be made from beads 
alone, or from beads and plain uncolored straws, or 
the straws may be dyed different colors by means 
of aniline dyes, or by dipping them into thin colored 
lacquers. 

A curtain or portiere of bamboo and beads is made 
in the same way, but on a larger scale. 

It is easy to make a good imitation of these curtains 
with paper tubes and beads, or the tubes alone. The 
manner of making these tubes is shown in Fig. 56. The 
])aper from Avliich the tubes are made should not be 
thicker than common writing paper. It may be either 
colored or white. The best results will be secured by 
using common white writing paper and coloring the 
tubes after they are formed and dry, by means of thin 
brown or white shellac varnish, colored Avith pigments 
or the anilines. 

The pieces of paper from which the tubes are made 
are preferably cut in trapezoidal shape, as shown at 
1 and 2, so that when the tube is finished it will have 
conical ends, as shown at 5, G, and 7. The wire shown 
at 3 is used as a mandrel upon which to roll the paper. 
The larger end of the piece of paper is applied to the 
A^'ire when the paper is rolled up in the manner illus- 
trated at 4. The narrower end of the paper is gummed 
and pressed down closely, when the ware is removed 



60 HOME MECHANICS FOE AMATEUES 




Fig. 57. Curtain formed of Straw, Bamboo, or Paper, and Beads. 



HOME MECIIAXICS FOIl A:yrATEUES 01 

;ui(I tlie opc^ration is repeated. It is not advautaueous 
to i»uiii the entire surface of the paper. Fastening at 
the end is sultieient. The wire nsed as a mandrel should 
not be more than one-sixteenth inch in diameter, as 
too large a hole through the rolls allows them to ar- 
range themselves irregularly. At 7 is shown a part of 
a lash formed of a long tube, a bead, and a short tube. 

In stringing both the straws and the paper tubes a 
long slim needle will be required. If this is not ob- 
tainable, a. ver}^ good substitute for it may be made by 
forming an eye or loop on the end of a thin wire of 
suitable length. 

There is scarcely any limit to the amount of labor 
that may be expended upon an article of this kind; 
but very pleasing results will be secured by the adop- 
tion of simple designs, which may be easily carried 
out. 

in]pousi8E 

This art, as practiced by the silversmith and the art- 
ist, is almost entirely dependent upon the manual dex- 
terity of the operator. A kind of repousse is here sug- 
gested which depends more upon appliances than skill. 
It is not, however, assumed that any set of devices can 
be made to serve in lieu of taste and judgment. 

To carry out this method, a piece of heavy cotton 
lace, or heavy open work fabric, or a piece of a basket 
may be glued to a block of hard Avood to serve as a sort 
of die for producing the impression in the metal. The 
fabric or basket work is not only attached to the 
block by means of glue, but its finer interstices are 
filled with glue so as to present a surface resembling 
the original fabric only in the most general way. 



62 



HOME MECHANICS FOli AMATEUKS 



When the glue is perfectly dry and hard, the die is 
laid upon a solid foundation, and a piece of very 
thin, soft copper or brass is secured to the block so 




Fig. 58. Embossing Thin Metal. 




Fig. 59. Basket Pattern. 

as to cover the lace as shown in Fig. 58. A piece of 
cork, about i inch thick, and about three inches wide 
and B or 8 inches long, is laid over the metal and 



HOME MECHANICS FOR AMATEURS 



63 



struck with a mallet, as shown. The cork yields suf- 
ficiently to push the metal clown upon the die, and 
cause it to take the pattern of the lace or whatever 
is used in formin<>' the die. A piece of rather hard 
rubber packing- will answer tliis purpose equally as 
well as the cork. 




Fig. 60. Die formed of Pasteboard. 

Designs may be cut from strong* paper or pasteboard, 
and glued to the block. Fig. 60 shows a design which 
may be reproduced in this manner. 

In Fig. 61 is represented a stencil design to be sawed 



64 



BOUE MECHANICS FOE AMATEIIES 







Fig. 61. Stencil Pattern. 

from hard wood. The Hues and scrolls are discon- 
tinued in places so as to cause the wood to hold to- 
gether. If it is desired to render the lines continuous 
at these points, they may l)e run through with a V- 
tool. The dots are picked out with a small gouge or 



'2:^x:^^22:^22sa;X 



^MlUiiLillA^^ 

Fig. 62. Rope Pattern. 




HOME MECHANICS FOE AMATEUES 65 

tlie point of a revolving drill. In all these cases the 
metal is attached to tlie block and treated as shown 
in Fig. 58. 

In Fig. 62 is represented in side elevation and in 
section a die formed of a small rope, glued in a semi- 
circular groove in a bar of hard wood. The embossing 
is done in the manner before described. In this case 
a thick piece of soft rubber is preferable to cork for 
forcing the metal into the depression of the die. 




Fig. 63. Vase formed of Embossed Plates. 

Either panels or continuous strips may be embossed 
in the manner described, and these are to be used in 
making frames, vases, and various ornamental objects. 
If the metal is too thin for a certain case, it may be 
strengthened by flowing soft solder over the back of the 
plate by means of a soldering iron. 

The vase shown in Fig. G3 is formed of four embossed 



66 HOME MECHAXICS FOR AMATEITES 

plates of copper, fastened to the back of four vertical 
brass strips b}^ solder, the whole being' secured to the 
bottom piece in the same manner. The bottom consists 
of a disk of copper soldered in. The base is formed of a 
brass stove-pipe collar soldered to the lower part of the 
body of the vase. The rim around the top consists of a 
strip embossed on the rope die. 




Fig. 64. A Bas-relief in Lead. Copper, or Brass. 

As to finish, any of the usual methods of brass finish- 
ing should be employed. This vase is esjiecially 
adapted for containing a palm or other large foliage 
plant. The earth and roots may be placed directly 
in the vase or they may be contained by a pot which is 
enclosed by the vase. 



HOME MECHANICS FOE AMATEURS 



67 



It is obvious that vases of other forms and other em- 
bossed designs may be made on this plan. 

Bas-reliefs may easily be made by a method which 
is a modification of the one described. Fig. 64 shows 
such a relief, and Figs. 65 and 66 illustrate the tools 
required for making it. 

To the wooden frame, A, is fitted a board, B, upon 




Pig. 65. Frame and Form for making the Bas-reliefs. 



which is drawn in outline the design which is to be 
produced in relief. The board may be of pine or any 
close-grained soft wood for lead work ; but for brass or 
copper, the wood should be hard. To the frame, A, is 
attached the plate of metal by means of screws. 

The board, B, is removed from the frame, and the 



68 



HOME MECHANICS FOE AMATEURS 



portion of the design which is to form the most promi- 
nent feature of the relief is sawed out of the board, 
when the latter is replaced in the frame, and the metal 
is forced into the opening of the board by pressing upon 
the surface of the lead opposite the hole in the board, or 
by pounding it by means of the mallet, C, shown in Fig. 
66. As soon as this feature is complete, the next in 
order is sawed out of the board, and the operation is 




J) 



Fig. 66. Tools for Repousse. 



repeated until all of the general features are developed. 
The progress of tlie work can be observed at any time 
by removing the board, B. 

The features may be corrected or modified by work- 
ing from either side of the plate by means of the con- 
vex mallet and the wooden punches and chisels, D 
(Fig. 66). If a support is desired for any part while 
the work is progressing, a stout bag filled with sand 
may be placed under the part. A few very small bags, 



HOME MECHANICS FOR AMATEURS 



69 



say 1 inch or 1^ inches in diameter, will be found con- 
venient. If desired, the drapery or the background 
may be chased by means of hard wood or metal punches, 
bearing on their faces tlie desired figures. 

The relief, if of lead, looks well with an antique fin- 
ish. 

AN EASY METHOD OF PRODUCINCx BAS- 
EELIEFS 

The production of patterns from which to cast orna- 
mental articles is confined to a class of artisans who, 
by long experience in carving and modeling, have at- 
tained great excellence in workmanship. An amateur, 
while he may not hope to attain such excellence, and 





Fig. 67. 



Bas-reliefs in Wax. 



cannot expect to produce, by the usual processes and 
with limited practice, such exquisite articles as may be 
seen in many of the city shop-windows, may, if he pos- 
sesses even a modicum of artistic taste and skill, do 



something in that direction. 



70 



HOME MECHAmCS FOR AMATEURS 



The articles required to carry out the process are 
some thin sheets of semi-transparent wax, a Ivuife hav- 
ing a narrow, dull blade, and the printed or drawn 
design of the form to be produced. The backing, or sur- 
face on which the relief is made, may be of any of the 
materials of which patterns are commonly made. 




Fig. 69. A Scroll Design. 

Having given the backing the required form and 
located thereon the position of the relief, a sheet of wax 
is laid over the design and the extreme outline of the 
figure is traced on the surface of the wax with a dull 
point. The wax is now laid upon a smooth board and 
cut upon the line just made with the knife, the blade 
being slightly warm. The wax thus cut is now placed 



HOME MECHAXICS FOR AMATEUES ^1 

on the foundation or backino, and fastened by heating 
the knife bhide quite hot and touching the wax at sev- 
eral points, so as to cause it to melt and adhere to the 








Fig. 


70. 






^^Ma 


li^^ 


^^s^ 


p^^ 






hW 


Ml 


rA^ 


-^ 






^m 


^^ 


^1^ 


K^ 






^^ 


^m 


^^j\ 


-« 






^m 


^S 


J^d 


^ 






m^j 


i^a 


w^ 


■^mmiji 






L^m 


^^s 


J^p 


ISliO 







Fig. 71. 




Fig. 72. 
Patterns for Bas-reliefs. 



72 HOME MECHANICS FOR AMATEURS 

backing. Supposing this piece of wax to have the 
thickness required in the thinnest portion of the relief, 
another sheet is laid upon the design and traced within, 
and a small distance from, the outline of the design. It 
is cut and laid upon the first piece and made to adhere 
by pressing it down slightly. 

Another sheet of Avax is traced within the outline of 
the second, and cut and placed upon the two already 
secured to the backing, and so on until the design is 
produced in Avhat might be termed the rough. This 
stage is illustrated in Figs. 67 and 68, which are re- 
spectively front and edge views, which give the idea of 
the arrangement of the several sheets. 

After the sheets are placed upon one another in the 
manner first observed, the edges may be burnished 
doAvn by the rounded back of the knife, or by any 
smooth, rounded implement, which must be slightly 
warmed. 

Superfluous wax may be removed by scraping when 
cold, and indentations and interstices may be filled by 
adding a little wax. A scroll design is shown in Fig. 69. 

When the model is to be reproduced in metal cast in 
sand moulds, the wax should be slightly varnished with 
pattern varnish ; but when the design is to be produced 
in plaster, a mould of plaster may be taken from the 
model after it has been oiled. 

A bas-relief may be made in this way from a profile 
photograph or from an engraving. 

The process may be emplo^^ed to advantage in orna- 
menting patterns for the coarser and heavier kinds of 
work. 

Figs. 70, 71, and 72 represent surfaces ornamented in 
this manner. 



HOME MECHANICS FOR AMATEURS 



73 



ORNAMENTAL IRON WORK FOR, AMATEURS 

Although artistic wrought iron work dates from very 
early times, it was never more popular than it is at 
present. This remark applies especially to movable 




Fig. 73. Fig. 74. 

Iron Lamp Supports. 

articles such as tables, stands, racks of various kinds, 
fuel baskets, lamp supports, etc. Many of these arti- 
cles of recent manufacture are copies of antique ob- 
jects, while others are of modern design. As works of 



74 HOME MECHANICS FOR AMATEURS 

art they are fully equal, if not superior, to the speci- 
mens of earlier work. 

Now, while no imitation can ever equal the original 
article, it must be admitted that imitations often prove 
very satisfactory to those who can neither make nor 
purchase the real article. 

The examples of iron work here illustrated are styled 
imitations, as they are made without forging, i. e., the 
iron is bent either cold or hot, without the use of a 
hammer, while the iron bars or rods maintain their 
original cross section. Any one used to the hammer 
and anvil can, in addition to the curves, apply forged 
portions, or twist and forge the bars used in the scrolls. 



Fig. 75. Jaw for Bending. 

The only special tool used in making articles of this 
class is the steel jaw shown in Fig. 75. Its slot re- 
ceives the bar to be bent, and its flattened shank is 
designed to be held in an iron vise. A scroll is formed 
by placing the end of a bar in the jaw, and winding the 
bar around the jaw and upon itself, afterward unwind- 
ing the bar to open the spiral as much as may be re- 
quired. After the scroll is complete, the inner straight 
end of the bar is cut off by means of a hack saw. The 
sharp angles may also be bent by the use of the jaw. It 
will facilitate the operation if the bar is heated red hot 
at the point of bending. A hammer may prove useful 
in this part of the operation. 



HOME MECHANICS FOR AMATEUES 75 

The standard of the lamp support consists of a piece 
of gas pipe. The feet are attached by means of screws, 
and the different parts of the iron work are fastened 
together by means of small screws or bolts. 

A rod is fitted to the gas pipe and has at its upper 
end a frame or cup for receiving the lamp. A clamp- 
ing screw passing through the gas pipe holds the rod at 
the desired height. 

An easy and satisfactory way of blacking the work 
after it is finished is to coat it with a thin varnish 
of stick or seed lac cut in alcohol, with refined lamp- 
black stirred in to give it the required color. The var- 
nish should be made quite thin to avoid any gloSvS, and 
should be strained through cheesecloth or similar 
material. 

It is obvious that grilles, gates, screens, doors, and 
other objects may be made from iron in this way with 
little trouble or expense. 

SOME THINGS IN WIRE 

There is scarcely a limit to the number of useful and 
ornamental things that can be made from wire. Two 
examples are shown in the engravings. Figs. 76 and 77, 
representing respectively front and edge views of a 
newspaper and magazine holder formed of a wooden 
back and wire scrolls; Fig. 78 showing a small wire 
stand or card receiver having a zylonite top. 

The scrolls of the newspaper holder are formed of 
three-sixteenths inch square brass wire; the several 
pieces being bent in the form shown and held in place 
by clips of the same material soft-soldered by means of 
a blowpipe. The overlapping portions of the scrolls 



76 



HOME MECHANICS FOR AMATEUES 



are also soft soldered. The lower part of each main 
scroll is held by a strong staple passing over the wire 
of the scroll and through the cleat and backboard and 
clinched on the back of the board. The three wires at 
the center of each scroll are prolonged below the cleat, 
as shown, to form a stop for limiting the swing of the 
scroll. 




Fig. 76. Newspaper Holder. 



Fig. 77. Edge View of 
Newspaper Holder. 



If care is taken in soldering the clips, the brasswork 
will require little preparation for lacquering. A stiff 
brush charged with finely powdered pumice wet with 
water and applied vigorously to the work will quickly 
remove all stains, and will give the work a uniform ap- 



HOME MECHANICS FOR AMATEURS 



77 



pearance. The backboard, which may be of walnut, 
mahogany, cherry, oak, ash, or maple, should be var- 
nished and well rubbed down before the cleats are 
applied. 

A holder of this kind will receive a large number of 
periodicals. 

The wire stand or card receiver, shown in Fig. 78, is 




Fig. 78. Wire Stand or Card Receiver. 



made of one-quarter inch or three-eighths inch round 
brass wire. It may be made of brass tubing three- 
eighths inch or one-half inch outside diameter and 
rather thick. In this case the tubes are annealed and 
filled with lead before bending. The lead is melted out 



78 HOME MECHx\NICS FOE AMATEURS 

of the tubes after bending. The spirals are formed 
separately by wrapping the tube or wire around a 
cylindrical bar of wood or iron in a close helical coil, 
then stretching out the coils, placing them together, 
as shown. They are then clamped on a smaller cylin- 
drical bar and their upper ends are twisted together. 
Two rings surround the loAver part of the spiral and 
to these rings are secured the legs by means of solder 
or screws. 

The small rings surrounding the legs may be pur- 
chased and secured in place by solder. 

The top of the stand consists of a disk of wood, con- 
caved at the top and furnished with an embossed disk 
of zylonite. 

The under surface of the stand top is provided with 
a perforated block, which fits over the closely twisted 
end on the standard. This receiver may be made so 
small as to stand upon a table, or it may be made of 
the usual table height. 



SOME THINGS IN BURNISHED BRASS 

The old and commendable fashion of making orna- 
mental objects from solid hand-wrought metal is being 
revived to a wonderful extent. Steel, iron, brass, and 
copper are wrought into a thousand beautiful and use- 
ful forms, and the gilded and tinsel objects of recent 
days are now set aside for substantial and elegant solid 
cast and hand- wrought ornaments. It will require only 
a suggestion to set the amateur mechanic at work at 
this sort of thing, when his dwelling will soon be 
adorned with articles that will be the more valuable 
for having been produced at home. 



HOME MECHANICS FOE AMATEURS 79 




Fig. 79. A Brass Easel. 



80 



HOME MECHANICS FOR AMATEUKS 



Brass tubing and rods of round, hexagonal and oc- 
tagonal section, plain and perforated strips of different 
widths and thicknesses, half round and semi-hexagonal 
strips, and brass buttons, knobs, and nails of various 
shapes, may be purchased so that the amateur will 




Fig. 80. A Brass Frame. 



readily find available materials for the kind of work 
suggested. Half-inch square tubes, strips of brass half 
an inch by one-sixth of an inch, a few brass buttons, 
and a few knobs, are required for the easel shown in 



HOME MECHANICS FOR AMATEURS 



81 



Fig. 79. The tubes may be draw-filed, then finished 
with the different grades of emery paper with oil, or 
they may be polished on an emery wheel, and the final 
finish may be imparted by using the finest French 
emery paper with oil. 

When two tubes cross each other they may be halved 




Fig. 81. A Nautilus Card Receiver. 



together precisely as in wood work, and may be fas- 
tened by soldering wdth soft solder. 

When the end of a tube abuts against the side of an- 
other tube it may be fastened solid enough for all 
practical purposes by soft soldering by means of a 
blowpipe. Of course the joint may be brazed or sol- 



82 



HOME MECHANICS FOE AMATEURS 



dered with silver solder, but as great strength is not 
required, it is unnecessary to take that amount of 
trouble. 

A very good way of fastening is to solder a plug in 
the end of the tube that abuts against the side of 
another tube, and to put a screw laterally through one 
into the plug in the other. In this case it is well to leave 
a slight feather on opposite sides of the abutting tube 




Fig. 82. A Brass Clock. 



to engage the corners of the tube to which it is at- 
tached. 

The scrolls should be attached by means of small 
screws. The panels consist of thin pieces of board cov- 
ered Avith velvet or plush of any suitable color. They 
are inserted from the back, and are provided with a 
number of large convex nails. The support for the pic- 
ture is movable up and down on the side pieces of the 



HOME MECHANICS FOE AMATEUES 83 

easel, and may be secured at any desired point by the 
milled screws. 

The frame shown in Fig. 80 will require no special 
description. The main portion of it is made of square 
brass tubing. The side bars are made of round brass 




Fig. 83. A Brass Table. 

rods with turned end pieces, as shown. The mat of 
thin wood is covered with velvet or plush. The picture 
and glass are placed behind the mat ; the latter is pro- 
vided with small brass ears wdiich are fastened to the 
back of the frame by screws. The knobs at the top, 



84 



HOME MECHANICS FOE AMATEUES 



bottom, and sides of the frame and easel are turned and 
attached with solder. 

Fig. 81 shows a tripod stand for a nautilus shell, with 
an ornamental shell placed below it in the center of the 
plate, forming the triangular base. Fig. 82 shows a 
clock case, consisting of an ordinary box of suitable 
size covered with plush or velvet, and inclosed in a 
frame of brass. 

The frame is built up in the manner already de- 
scribed from square brass tubing split lengthwise 
through diagonally opposite corners. The lower por- 




FiG. 84. Examples of Paneling. 



tion of the frame consists of a wide band of brass, hav- 
ing a light bead soldered to its upper edge and a heavy 
bead soldered to its loAver edge. A number of the brass 
nails are placed at regular intervals and soldered at 
the back of the brass base. The rail at the top is made 
of hexagonal brass tubing, and the small balusters are 
turned from brass rods. The palette and brushes are 
sawed from a plate of brass and attached by tacks 
soldered to the back. The patches of color are pro- 
duced by different colors of sealing wax. Four brass 
nails are inserted around the dial to relieve the blank 



HOME MECHANICS IQE AMATEUKS 85 

spaces on the plush. The dock and its plush-covered 
case may be removed from the brass frame when it is 
desired to clean the latter. 

The table shown in Fig. 83 is of the same general 
character as the other articles, and will not, therefore, 
need particular description. The central portion is of 
three-quarters inch round brass tubing. The legs are 
of five-eighths square brass tubing. The top is of 
wood, plush-covered and fringed, and provided with a 
border of perforated brass. 

Fig. 84 shows different kinds of panels. The balus- 
ters in the upper one are turned ; in the two lower ones 
they are cut from sheet metal. 

All of these articles may be lacquered, but they pre- 
sent a more elegant appearance if the metal is left un- 
protected and cleaned occasionally with rottenstone 
and oil. 

There is hardly any limit to the number of pretty 
and useful articles that may be made of such materials, 
with the expenditure of little thought and labor. 

FORMING PLASTER OBJECTS 

It is sometimes convenient to form objects of cir- 
cular section from plaster of Paris. This is a very sim- 
ple operation, requiring only very simple tools and 
apparatus. An iron rod, bent at one end to form a 
crank, and carrying a conical wooden roller, two 
notched bars of wood for supporting the iron rod, and 
a pattern made from a thin piece of hard wood, com- 
prise the outfit for making these articles. The rod is 
held in its bearings in the bars by pins inserted 
obliquely in holes in the wood, so as to project over 



86 



HOME MECHANICS FOR AMATEURS 



the rod. The pattern is cut so that its edge is a profile 
of one side of the article to be made. The wood should 
be made thin on the working edge. The patterns may 
be made to advantage of metal backed by wood. 

The conical wooden roller should be flattened on 
three or four sides to prevent the plaster from turning 
around on it. The roller is oiled or smeared over with 
grease, and a batter of plaster of Paris is prepared by 
mixing the dry plaster with water to the consistency of 
cream. As soon as the plaster begins to set it is applied 
plenteously to the roller, and while the rod is turned 




Fig. 85. Forming Plaster Objects. 



by means of the crank the pattern is moved forward 
toward the rod, and the surplus plaster is removed by 
the pattern which acts as a scraper. Any deficiencies 
are supplied by a new application of the batter. 

When the object is of the right size and form, the 
pattern is removed and cleaned, and again applied to 
the object, the latter having been brushed over freely 
with water. This gives the finishing touch. 

After the plaster becomes perfectly dry and hard, 
the roller is knocked out, and the object is subjected to 



HOME MECHANICS FOR AMATEUES 87 

a dry heat at a temperature of about 212 degrees Falir. 
for an hour or so. It is then brushed over with thin 
glue size until it has absorbed as much as possible, 
when it is allowed to dry for several days. The latter 
treatment renders the plaster hard and strong. 

The final operation consists in painting, lacquering 
or bronzing the object, as taste may dictate. 



PART III. 

METAL WORKING 

SAWING METALS 

A GREAT DEAL of hard labor in working 
metals may be avoided by the use of hack 
saws and jeweler's saws. The large hack 
saw has a malleable iron frame and a handle 
and tail piece which will revolve so as to adjust 
the saw to any desired angle. The tail piece has an 
adjusting screw by which the tension of the saw may 
be regulated. Several kinds of saws can be used in 
this frame, /. c, saws with coarse and tine teeth, which 
are set more or less according to the kind of metal on 
which they are used. These saws all have very hard 
teeth, but the main portion is soft, so that the saw 
does not readily break. These saws are cheap, and 
when one becomes dull or is broken it is replaced by 
another. They are so hard they cannot be tiled. 

The next saw in size has a heavy wire frame. Slits 
are cut in opposite ends of the frame to secure the saw, 
and small pins extending through holes in the ends of 
the saw rest in notches cut in the frame. The spring 
of the frame holds the saw under tension. To put in a 
new saw, the ends of the frame are sprung inwardly 
with considerable pressure. The saws for this frame 
are also hardened on the toothed edge, the remainder 
being soft. They are much thinner than the large saws. 
The smaller saw frame is adjustable as to length and 
is designed to receive very small saws made from mate- 
rial like watch springs. 

[89] 



GO HOME MECHANICS FOR AMATEUES 

This saw is for more delicate work than the others. 
No attempt is made to sharpen them with a file. A dull 
one is thrown away and replaced by a new one. 

There are many kinds of work in which a great deal 
of time and labor may be saved by the use of these 
saws ; for example, cutting off iron, steel and brass bars 
and tubes, cutting various straps out of thick sheet 
brass; cutting slots in work when required. They 
may also be used in place of files in places where a file 
cannot be introduced. 

SOLDERING 
Nothing is more useful for the amateur than a knowl- 
edge of the art of soldering. It is a very simple one, 



x^ 


\ 




"'^.. .«.- 


'^ jBter 


1 i*^ ^S?^,iii • 


fn^' ' -^j^sifcfc-- - 




mB 



Fig. 86. Articles used in Soldering. 

the tools required are inexpensive, and there is real 
satisfaction in doing it rather than being delayed to 
employ a regular tinsmith or other mechanic. 

The soldering iron consists of a small oblong block 
of copper, pointed at one end and having a large wire 
screwed into the other end, the wire being provided 
with a wooden handle. Some soft solder will be re- 
quired, say a quarter or half pound. It is better to buy 



HOME MECHAXICS FOE AMATEUES 91 

this in the form of solder wire, l)ut it can be readily 
made by melting together equal parts of pure tin and 
pure lead. 

To carry on the work a small box of pulyerized rosin 
and a bottle of soldering fluid will be required. 

The soldering fluid can be purchased. It is readily 
made by filling a small bottle half full of hydrochloric 
acid. (This acid must be handled with care as it is 
poisonous and yery corrosiye.) Into the acid drop lit- 
tle strips of zinc, a few at a time, until it will dissolye 
no more. This operation must be done in the open air, 
as the fumes are sutfocating and injurious, ^lien the 
boiling of the acid ceases the bottle should be filled up 
with water and closed with a rubber stopper. In addi- 
tion to these things already mentioned a small tin 
box containing a wet cloth will be required. 

Before soldering can be done the copper must be 
heated so that it will melt the solder readily. Then 
the pointed end must be cleaned with a file and a piece 
of the solder wire is dipped in the soldering fluid. 
When the end of the wire wet with the fluid is placed in 
contact with the side of the hot soldering iron it will 
melt and the soldering fluid will cause the solder to ad- 
here to the copper. This may be repeated until the four 
sides of the pointed end are coyered with solder, or 
^'tinned" as the smiths haye it. 

To solder, the joint to be made is scraped clean ; then 
a yery small amount of the soldering fluid is applied 
if the work to be soldered is iron or copper, or brass, 
but if it is bright tin a little of the rosin \sill answer 
rather better than the acid. The iron is to be heated, 
not too hot, howeyer. then quickly wiped on the damp 
cloth and applied to the solder, to take up a drop, then 



92 HOME MECHANICS FOE AMATEUES 

placed on the joint and moved slowly alon^, allowing 
the solder to follow. If the tinning is burned off the 
soldering iron, it must of course be retinned. The 
secret of success in soldering is to have the iron just hot 
enough, and to have the surface to which the solder is 
applied very clean. 

GRINDING AND POLISHING 

Removing surplus metal by grinding, sharpening 
tools, and smoothing and finishing work are most readi- 
ly accomplished by the amateur by means of emery 
wheels of various degrees of fineness, or corundum or 
carborundum wheels used in the lathe. If a fine lathe 
is available, the wheels may be carried by suitable steel 
mandrels mounted between the lathe centers, or by a 
single mandrel held by a chuck ; but when these things 
are not available, the wheels may be mounted on a hard 
wood mandrel. The mandrel has a shoulder against 
which the wheel is clamped by a wooden collar, and a 
pin or key passing through a hole in the mandrel. 
Washers of leather or pasteboard may be used to adapt 
the mandrel to emery wheels of different thicknesses. 
In selecting an emery wheel, one should be chosen 
which will cut freely without glazing. Such wheels 
revolved in a lathe cut rapidly and serve well for re- 
moving surplus metal and for sharpening tools. A 
rather fine wheel is preferable to a coarse one for the 
latter purpose. 

For polishing, a wheel may be made of a disk of wood 
turned in the lathe and covered on its periphery or side 
or both w^ith leather. Sole leather Avhich contains no 
oil or grease is the best for the purpose. If the leather- 



HOME MECHANICS FOR AMATEURS 93 

covered wheel is not true it may be turned off in the 
lathe and smoothed with fine sandpaper. The leather 
on the edge of the wheel should be scarfed and lapped 
so as to make a smooth joint. 

After the leatlier is properly finished it should be 
coated witn emery of the degree of fineness required. 
This is done by warming the wheel, coating it with 
strong glue and rolling it i'U the powdered emery. To 
insure a good job, the emery itself should be warm. 
Probably the best way to secure good results is to 
spread the emery out on a flat metal plate which has 
been heated. The leather-covered wheels are very use- 
ful. They may even be used in place of the solid emery 
wheel in many kinds of work. If they are used care- 
fulW they will last a long time After one is partly 
worn it is even more useful than it is when new. For 
polishing steel a leather-covered wheel of the kind de- 
scribed charged with crocus instead of emery will be 
required, also another charged with fine rouge or putty 
powder for a very fine finish. For buffing silver and 
other soft metals a wheel of chamois skin or buck- 
skin drawn over a padding of soft felt and tacked at 
the sides of the wheel will be found valuable. The skin 
will have to be lapped on the periphery of the wheel, 
but it cannot be glued. Fine rouge is the best to apply 
to this wheel. For polishing irregular surfaces bristle 
brushes must be used, a coarse brush charged with 
powdered pumice stone for doing the rougher work; 
this to be followed by a finer brush charged with tripoli 
or whiting and water. 

The brushes, which have wooden hubs, are carried by 
tapering screws held in the lathe chuck or inserted in 
the mandrel in place of one of the centers. 



94 HOME MECHAXICS FOR AMATEURS 

SILVER WORK 

Silver is not a very expensive material for the manu- 
facture of small objects, and it is easily worked and 
finished. The objects when finished have an intrinsic 
value, and if the effort to produce a fine article results 
in failure, the material is not lost ; it can be sold as old 
silver, with little loss. 

The engraving shows articles which an amateur can 
make. The bonbon dish and spoon shown in the illus- 
tration were quickly made by an amateur silversmith. 





.-^s. 


^ /f 




|^:^|^ 




< 





Fig. 87. Examples of Silver Work. 

It is first folded in the center, then opened and folded 
at right angles to the first fold ; then opened and folded 
again parallel with the first fold, and so on until the 
entire surface is crossed with folds about three-fourths 
of an inch apart. The edges are turned up all around 
for about f of an inch, and the corners are 
crimped a little, and small folds are made. The whole 
W'Ork up to this point can be done with the fingers 
alone. The folds at the corners are hammered down 



HOME MECHAXICS FOR AMATEURS 95 

with a wooden mallet while the sheet rests at the corner 
on a round support. From time to time the silver 
should be annealed, i. c, heated to a low red heat, and 
plunged into cool water. This will permit of bending 
the silver without breaking it. 

Little folds should be made in the sides at the upper 
edges if necessary, to allow the sides to be straightened ; 
then the upper edge should be trimmed off with shears, 
so that the dish is the same height all around. Then a 
piece of hollow silver wire which has not been soldered 
is opened slightly at the seam by drawing a knife 
through the seam. A piece of this wire long enough 
to reach around the upper edge of the dish is slipped 
over the upper edge of the dish and soldered at differ- 
ent points, with silver solder. If this is not within the 
power of the amateur, he may attach it at frequent in- 
tervals by means of very snmll pieces of soft solder 
melted after the application of a very minute quantity 
of soldering fluid, b}^ holding the edge of the dish with 
a pair of pliers over a gas flame two or three inches 
above the top of the flame. If this is carefully done, the 
small particles of solder Avill soak into the joint and 
become invisible. Across the corner of the dish is se- 
cured a tree limb made of silver, and on this are secured 
the birds. The silver limb is made by hammering a 
stout silver wire into a half-round notch in the end of a 
piece of steel, grooves being formed in the notch to give 
the flattened wire the appearance of having bark on it. 
The birds are of special make, used for other purposes. 
If the amateur silversmith desires to use the birds he 
will be obliged to purchase them, as they cannot readily 
be made by one having no experience in this line. They 
are of bronze and are colored. 



96 HOME MECHANICS FOR AMATEUES 

This particular dish was oxidized before the birds 
were applied. The dish was oxidized by immersing it 
for a few minutes in a solution of bisulphuret of soda. 
It was then washed and dried and the oxide was re- 
moved from the projecting portions by means of a 
chamois skin charged with rouge. This dish may read- 
ily be made round, elliptical, or triangular, as taste 
may indicate. It is well in a case like this to try the 
experiment of making the dish in copper or soft brass 
before trying silver. 

METAL FOOT LATHE 

The amateur after using the simple wooden lathe will 
no doubt ask for something more pretentious, a lathe 
that can be used for working metals in various ways, 
and drilling and turning hard wood, horn, ivory, rub- 
ber, etc. Lathes vary in price from ?15 to |50 and up- 
ward. In fact, almost any amount of money may be 
invested in a foot lathe and the accessories which can 
be used in connection with it to great advantage. 

The better way to proceed is to purchase a lathe 
complete, with fly-wheel, treadle, belt, chucks for turn- 
ing wood, centers for turning metals, a face plate, one 
or two lathe dogs, a drill chuck, three or four hand 
tools for turning brass and other metals, and three or 
four tools for turning wood. 

Not a great deal can be said in regard to the various 
kinds of work to be done on a foot lathe of this kind. 
More can be learned in a half hour by the observation 
of a skilled workman than can be acquired by a day's 
practice, or by a ^tudy of books. However, any one 
having a mechanical turn of mind can take the various 



HOME MECHANICS FOR AMATEURS 97 

tools, and with the aid of a little common sense can 
soon master the art of hand turning. 

After practice with the lathe the amateur soon finds 
that other tools are required, and he will either make 
them or hiij them, and thus gradually add to his outfit 
until he is able to undertake any work that may come 
along. 

To turn longer pieces of metal than can be held ad- 
vantageously in the chuck, the pieces are centered, 
drilled, and then countersunk to fit the centers of the 
lathe, one of which is in the mandrel, the other in the 
tail-stock spindle. A lathe dog is placed on one end 
of the i)iece of metal and inserted in the slot in the 
face plate of the lathe, while the lathe center is inserted 
in the countersunk drill-hole in the end of the bar to be 
turned. The center carried by the tail-stock is brought 
forward and inserted. The tail-stock is then made fast 
to the lathe bed, and the center is adjusted by turning 
the tail-stock screw ; the work should turn easily with- 
out chattering and the center should be oiled. 

It is a good plan to finish the work without filing, 
but the file and emery paper may be used ; they should 
be used with care, however, as they are liable to injure 
the angles and finer features of the work. A tool will 
give a fine finish on steel work if it is sharpened on a 
fine oil stone and the work is wet with oil or some 
other liquid ; even saliva is often made use of with good 
effect. Brass and other materials softer than steel are 
readily turned in any form desired, and of course hard 
rubber and hard and soft woods are still more easily 
worked. 

Turning brass. Babbitt metal, or type metal is not 
materially different from turning hard wood. The tools 



98 HOME MECHANICS FOE AMATEURS 

are practically the same, and the methods are the same, 
but the metal turning is done at a somewhat slower 
speed. In the case of metals, the finishing of the sharp- 
ening of the turning tools is done on an oil stone to 
insure the smoothness of the work. The work should 
be so smoothly done that no final finishing will be 
required. If, however, brass work is to be finished it 
may be done by means of very fine emery paper or 
cloth. This may be applied by the hand or strips of it 
may be glued on flat or convex strips of wood which are 
used in the same manner as a file. 

The amateur cannot expect to cut screw threads with 
chasers as readily as a skilled mechanic, but he can 
make some headway with practice on brass and hard 
wood. Chasers may be purchased for cutting inside 
and outside threads. The chaser is moved along the 
lathe rest at what is judged to be the speed the thread 
would carry it along if already cut in the brass or 
wood. The chaser is at the same time pressed firmly 
on the rest and brought into engagement with the ma- 
terial revolving in the lathe. 

Make-shifts are not to be generally approved, but 
the writer will relate a circumstance which came to his 
knowledge some years ago that may be helpful to some 
one caught in a similar predicament. 

A lathe was available but no screw-cutting tools of 
any kind were at hand. It was necessary to make one 
or two fittings for a half-inch gas pipe. Tw^o old files 
were found and annealed, and in the end of one were 
filed with an ordinary triangular file the teeth to fit the 
threads of the gas pipe. In the side of the other file 
were filed teeth to fit the teeth of the first chaser. 
These teeth were filed at a slight inclination to cor- 



HOME MECHANICS FOR AMATEURS 99 

respond roughly with the pitch of the screw thread. 
These chasers were hardened and tempered and used to 
good advantage in finishing work which would other- 
wise have been delayed at considerable inconvenience. 



METAL-WORKIKG ON A LATHE 

INSTRUCTIONS ABOUT DRILLS AND 
DRILLING 

An ordinary flat drill for most purposes will answer 
nearly, if not quite, as well as a twist drill. It is not 
a difficult matter to make them, since we have such 
reliable material as Stubs' steel wire of every size. The 
best form of flat drill for general purposes is shown in 
Figs. 88, 89, and 90. It is made by milling or flling the 
opposite sides of the wire, so as to form a bit or blade 
having a thickness equal to about one-fourth of the 
diameter of the wire. The angle of the point should be 
90 degrees, and the angle of its cutting edge about 45 
degrees for most uses. For a drill for very hard sub- 
stances these angles may be more obtuse. 

Having formed the drill, it should be hardened by 
heating it to a low red and plunging it straight down 
into cool (not cold) water. In case of a very small 
drill, it may be held in the flame of a gas burner or 
lamp in a pair of spring nippers over a vessel of water. 
^yhen it attains the required degree of heat it may be 
dropped into the water. 

To temper for most cases, the drill, after being 
brightened on an emery wheel or piece of emery paper, 
is heated ; if it is a small one, in an alcohol or gas flame, 
until its color at the point runs down to a brownish 



L.ofC. 



100 HOME MECHANICS FOR zVMATETJRS 



yellow verging^ on a purple. If the drill is very large 
it may be heated over a forge fire, or over a heavy piece 
of red-hot iron. If the drill is a very small one, it may 
be hardened and tempered at one operation by heating 
to a low red heat and plunging it immediately into a 
piece of beeswax. 




and 89. Tempering. 



If it is desired to have the point of the drill very hard, 
without being liable to breakage, its temper may be 
drawn by holding its point in pliers, as shown in Fig. 
88, while the main portion is held over a gas flame. 
The cool jaws of the pliers prevent the point from be- 
coming heated. 

Another method, applicable to larger drills, is to em- 
ploy a notched block of lead, as shown in Fig. 89. The 
drill in this case is driven a short distance into the 
lead before it is hardened ; then, as it is tempered, it is 
replaced in the lead to preserve the hardness of the 
cutting edges while the temper is drawn in the other 
portions. 



HOME MECHANICS FOK AMATEUES 101 

When a drill is liardciied by immersing its point in 
mercury instead of water, it acquires a diamond-like 
hardness. The point of the drill jnst described is 
shown in perspective and in section at D in Fig. 90. 
The drill F is similar to the drill D, the point of dif- 
ference being a half-round groove along each face ad- 
jacent to the cutting edge. This device gives the cut- 
ting edge a more acute angle, which is desirable for 
some kinds of work. G is a .straight drill having con- 
cave or fluted sides, and E is the well known twist 
drill. The drills, G E, are shown in cross section in 
the central figure. Twist drills of recent manufacture 
have a central longitudinal line, which locates the point 
in grinding. 

The best rule for grinding twist drills is to preserve 
as nearly as possible the original form. The ordinary 
pin drill, H, is used for counterboring, a hole being 
first drilled to receive the pin. The drill I is employed 
to give an ornamental appearance to plates in which 
pivots or small shafts are journaled, as in clock work. 
The bottoming drill, J, has three cutting edges, one 
upon each side, and a central transverse one connecting 
the other two. This drill, as its name indicates, is de- 
signed to make a flat bottom in a drill hole. 

The pin drill, K, which is shown in side and end 
views in Fig. 93 is first carefully turned and afterward 
milled with the rose bit, L, producing the cutting points 
or lips, which are afterward beveled with a file. This 
drill is used for boring large holes in sheet metal, a 
small hole being drilled first to receive the pin. M is 
an expansion drill for the same purpose; its construc- 
tion will be readily understood from the engraving. 
The spindle is mortised to receive the tool carrying 



102 HOME MECHANICS FOE AMATEURS 

arm, which is secured in the mortise by a key. The 
lower end of the spindle is bored to receive the drill, 
which also forms the pin for guiding the cutter. 

While universal chucks are recommended for holding 
drills, another form of chuck, shown in Fig. 91, may 
be used with equal advantage. It consists of a main 




Fig. 90. Forms of Drills. 



portion. A, which screws on the lathe spindle, and has 
a tapering threaded end for receiving the milled nut, B. 
The threaded end is split to admit of its contraction as 
the nut, B, is screwed on. The part. A, is bored longi- 
tudinally to receive sections, C, of iron or steel rod. To 
prepare this chuck for holding drills, the pieces, C, 



HOME MECHANICS FOR AMATEURS 103 

are inserted in the chuck, centered with a pointed tool, 
and are drilled with the drill with which they are 
intended to be used. They are then split longitudinally 
with a saw for about three-fourths their length. The 
pieces, C, when once prepared, Avill always answer for 
the same sized drill; they may also be used with an 
ordinary chuck having a set screw. 




Fig. 91. Drill Chuck. 



The fluted countersink, O, may be classed among the 
drills; its special application is to form the centers of 
articles to be turned. It has the same form as the lathe 
centers, and makes a truly circular conical hole, provid- 
ing the number of flukes or cutting edges is odd. 

Every lathe should be provided with a plate, or drill 
rest, P, fitted to the tail spindle, for supporting plain 
work while drilling it. The lathe should also have a 



104 



HOME MECHANICS FOE AMATEURS 




HOME MECHAmCS FOR AMATEUES 



105 



hinged or pivoted rest, Q, which may be clamped at any 
desired angle for drilling irregular work. This plate 
should have several perforations for receiving pins, 
for preventing the work from slipping. For supporting- 
cylindrical objects to be drilled transversely, a fork, 
R, is inserted in the tail spindle. 




Fig. 93. Drills and a Rose Bit. 



As to the matter of drilling, little need be said, as 
nearh^ everything must be learned by experience; how- 
ever, a few points may be mentioned. The work should 
be carried forward with a regular and not too heavy 
pressure. The speed of the drill will vary with the ma- 
terial being worked. For steel, wrought iron, and cop- 
per, the speed should be slow ; for brass and cast iron, it 
may be quite rapid. In drilling steel or wrought iron, 
oil is the best lubricant for the drills; in drilling glass, 
the drill should be wet with turpentine. 



106 HOME MECHANICS FOR AMATEURS 



HINTS CONCERNING CENTERING AND 
STEADYING 

To center a cylindrical piece of metal readily and 
accurately is a very simple matter when the workman 
is provided with tools especially designed for the pur- 
pose, and it is not difficult when an engine lathe or even 
an engine rest is available; but to do it easily and prop- 
erly in an ordinary plain foot lathe may puzzle some of 




Jiiliiii"!il|l;!jiill' 
Fig. 94. Centering with a Forked Tool. 

the amateur mechanicians. Although some of these 
methods are well known, they will nevertheless be de- 
scribed for the benefit of some Avho may require the in- 
formation. The method of centering shown in Fig. 94 
is one of the most common where the lathe is provided 
with an engine rest. A forked tool, A, is clamped in 
the tool post in such a position that a line drawn from 
the point of the tail center will bisect the 



HOME MECHANICS FOE AMATEURS 107 



angle of the fork. A square pointed center, 
G, is inserted in the tail spindle and moved 
against the end of the rod being centered with 




Fig. 95. Centering. 

a slight pressure, the tool, A, being at the same 
time moved forward by the screw of the engine rest un- 
til the rod turns smoothly in the fork and the square 




Fig. 96. Centering with a Hand Tool. 

pointed center lias found the center of the rod ; the tail 
spindle is then moved forward until the cavity is suffi- 
ciently deej) to permit of starting the center drill. The 



108 HOME MECHAlSriCS FOR AMATEUES 

angle of square center, G, for very hard material, 
should be a little more obtuse than that shown in Pig. 
97. In any case, it should be of good material and well 
tempered. 

In Fig. 95 is shown a centering tool which is designed 
to take the place of the engine rest and fork in Fig. 94. 
The part B is fitted in place of the ordinary tool rest. 




Pig. 97. 




Fig. 98. 





Fig. 100. 



and the jaw, C, which has in it a V-shaped notch, is 
hinged to the part B at D. A screw, E, passes through 
the upper end of the part B, and bears against the jaw, 
C. After what has already been said in connection 
with the engine rest, the manner of using this con- 
trivance will be readily understood. 

In Fig. 96 the hand tool, F, is employed for steadying 



HOME MECHxiNICS FOR AMATEUES 



109 



the shaft and bringing it to a center. This tool is bent 
to form a right-angled notch for receiving the shaft, 
and when in use it is supported b}^ the tool rest after 
the manner of an ordinary hand turning tool. 

Work that is too large to be readily centered in this 
manner is often centered approximately by means of 
the universal square, as shown in Fig. 98. A diamet- 




FiG. 103. 
Steadying Devices. 

rical line is draAvn along the tongue of the square, 
the work is then turned through a quarter of a revolu- 
tion, and another line is drawn. The intersection of 
these lines will be the center, at least approximately. 



no HOME MECHANICS FOR AMATEURS 




HOME MECHANICS FOR AMATEUES 111 

This point may now be marked with a center punch, 
and the work may be tested in a lathe. If it is found to 
revolve truly on the centers it may be drilled, otherwise 
the center must be corrected with the center punch, and 
the work again tested in the lathe. 

After centering by any of these methods, the center 
must be drilled and countersunk with a suitable tool, 
so that it will fit the lathe center, as shown in Fig. 99. 
The angle of the lathe centers should be sixty degrees. 
To insure uniformity in everything pertaining to the 
centers, the center gauge, shown in Fig. 100, should be 
used for getting the required angle on the lathe centers 
and on the drills used in centering. 

The matter of steadying the long, slender rods while 
being turned in the lathe is often perplexing. 

In some cases it may be done tolerably well in the 
manner illustrated in Fig. 101. The fork, H, is sup- 
ported by the standard, I, which is inserted in the 
socket of the rest support, J. The device shown in Fig. 
95 may be used in a similar way. 

Fig. 102 represents a steady rest, the construction of 
Avhich will hardly need explanation. For light work it 
may be made of wood ; the upright being secured to the 
cross piece, L, which rests upon the lathe bed. The 
slotted pieces, M, are adjustable lengthwise to accom- 
modate the size and position of the shaft. When it is 
required to support a bar which is not round, the sleeve, 
N, shown in Fig. 103, is employed. It slips over the 
shaft and revolves in the steady rest. The bar is cen- 
tered by the screws, O. 

The device shown in Fig. 101 is used where a hollow 
mandrel lathe is not at hand. A piece of gas pipe, Q, 
is held by the chuck, P, and is secured by a set screw in 



112 HOME MECHANICS FOR AMATEURS 



the sleeve, B, which is journaled in the standard, S, 
and carries the chuck, T. This arrangement may also 
be employed for turning the ends of long rods where it 
is not desirable to put them regularly on the centers of 
the lathe. 

CHUCKING 

In spite of all possible appliances to be used in a 
general way for chucking work in the lathe, a degree of 
inventive skill is often required to accomplish it quickly 




Fig. 105. Chucking a Metallic Disk. 

and securely. The accompanying cuts are designed to 
aid the amateur in chucking, but after all is said, there 
is a world of knowledge that can be gained by experi- 
ence only. 



HOME MECHANICS FOK AMATEURS 



113 



The arrangement of a metal disk in the lathe so that 
it can be turned on its face, and upon its edge, cannot 
well be accomplished by means of chucks ; for this pur- 
pose recourse is frequently had to cement. A good 




Fig. 106. Chucking a Spindle. 

cement for this purpose consists of Burgundy pitch, 2 
pounds; resin, 2 pounds; yellow wax, 2 ounces; dried 
whiting, 2 pounds; melt together the pitch, resin, and 
wax, and stir in the whiting. 




Fig. 107. Chucking Work on Face Plate. 

To chuck work with this cement, apply a small por- 
tion of it to a face plate devoted especially to this pur- 
pose; heat the plate so that the cement will cover the 



114 HOME MECHANICS FOE AMATEUKS 

greater portion of its surface. The plate may be al- 
lowed to cool. Whenever it is desirable to chuck a 
metallic disk, it is heated and placed against the cement 
on the face plate, and allowed, to remain until the 
cement begins to stiffen, when a tool having a right- 
angled notch is applied to the edge of the disk, as shown 
in the cut, the lathe being rotated until, by the com- 
pound action of the tool pressure and the rotary mo- 
tion, the disk becomes perfectly true. 

To chuck a spindle or any similar object a cement 
chuck like that shown in section in Fig. 106 is some- 
times used. The larger portion is screwed on the lathe 
mandrel, and the inner end of the hole in the outer por- 
tion terminates conically. The hole is filled with 
cement, and the article to be chucked is warmed and 
introduced. It may sometimes be necessary to heat the 
chuck with an alcohol or gas flame. The lathe is 
rotated, and the spindle is held lightly until it becomes 
true and the cement begins to harden. 

To remove the work from a cement chuck, it must be 
warmed by means of a lamp or otherwise. Most of the 
cement adhering to the work may be wiped off after 
heating it; whatever remains may be removed with a 
little turpentine. 

A common method of chucking work on the face plate 
is shown in Fig. 107 ; the Avheel is temporarily retained 
in place by a pointed rod. A, Avhich is forced against the 
wheel by the tail spindle. A little rapping one w ay or 
the other readily centers the wheel. A piece of crayon 
held in a crayon holder supported by the tool rest may 
be used to discover which side of the wheel is "out." 
After the wheel is trued, it is fastened by the short bars, 
B, whose outer ends rest upon any convenient blocking 



HOME MECHANICS FOR AMATEURS 115 



while they are drawn by the bolts, so as to clamp the 
wheel firmly to the face plate. 

It is sometimes preferable to use the yoke shown in 
Fig. 108 instead of the bars shown in Fig. 107 ; it is 
placed diametrically across the wheel and secured by 
two bolts. 




Fig. 108. Yoke. 

Fig. 109 represents a chuck consisting of a wooden 
disk, c, bored to receive the wooden hoop, d, which may 
be forced inward by the common wood screws, e, which 
bear upon it. This chuck is useful where a consider- 
able number of similar pieces are to be turned or bored. 




Fig. 109. Wood Chuck for Duplicate Work. 

Fig. 110 represents a simple and well known chuck. 
It is simply a block of wood secured to a face plate by 
a screw center and turned out to fit the work. 



116 HOME MECHANICS FOE AMATEUES 

Fig. Ill represents an easily made chuck, which is 
useful for holding plugs of wood to be turned or bored. 
It consists of a piece of hard wood fitted to the mandrel, 
turned, bored, and split longitudinally, as shown in the 





Fig. 110. 



Fig. 111. 




Fig. 112. 




Fig. 113. 
Chucking Devices. 

engraving. Its outer end is tapered, and to it is fitted a 
metallic ring that serves to contract the chuck when it 
is forced on. 

Fig. 112 represents a tapered and split mandrel. 



HOME MECHANICS FOR AMATEUES 



11? 



which ma^^ be either of metal or wood according to the 
purpose to Avhich it is to be applied. The part F is 
bored conically at the smaller end before splitting, and 
to this hole is fitted the conical plug, G, which being 
forced in expands the mandrel. 

In Fig. 113 the mandrel, C, has permanently attached 
to it the cone, D, and upon it is placed the movable 





Fig. 114. 
Chucking on Angle Plate. 



Fig. 115. 
Face Plate Jaw. 



cone, E, which is forced against the work held between 
the two cones by a nut which turns on the threaded end 
of the mandrel. 

In Fig. 114 the manner of chucking work on the 
angle plate, H, is shown so clearly as to require no 
explanation. It may be well, however, to state that 
when the work is rotated rapidly a counterbalance 



118 



HOME MECHANICS FOR AMATEURS 



should be attached to the face phite on the side dia- 
metrically opposite the angle plate. 

Fig. 115 shows a jaw for attachm^^nt to the face plate, 
which consists of a right-angled piece, I, a jaw, J, which 
has two guide pins, entering holes in the piece, I, and 
the screw, K, which passes through a tapped hole in 
the piece, I, and bears against the jaw, J. The piece, I, 
has a dowel, a, that keeps it from turning, and a screw, 
h^ by which it is secured to the face plate. 





Fig. 116. 



Fig. 117. 



In Figs. 116 and 117 the pin, L, is fitted to the face 
plate, and has formed on its projecting end an eccen- 
tric which fits the jaw, M. It has also a hexagonal head 
for receiving the wrench by which it is turned. Three 
pins, L, are fitted to the face plate, which is quite thick. 
Two of the pins need not be turned after being adjusted 
for a certain kind of work; the third is loosened and 
turned when work is put in and taken out of the lathe. 



HOME MECHAXICS FOE AMATEURS 119 

After the work is damped tightly by turning the eccen- 
tric the nut on the back of the face plate is tightened. 
In Fig. 118 is shown a type of the most convenient 
and most universally useful chuck in existence. Its 




Fig. 118. Scroll Chuck. 

construction and use are so well known as to need no 
description. The jaws are simultaneously moved to 
or from the piece of metal which is being machined by 
the aid of a kev. Such chucks hold drills admirably. 



METAL TURNING 

In selecting a lathe an amateur may exercise more or 
less taste, and he may be governed somewhat by the 
length of his purse; the same is true in the matter of 
chucks ; but when he comes to the selection or making 
of turning tools he must conform to fundamental prin- 
ciples ; he must profit as far as possible by the experi- 
ence of others, and will, after all, find enough to be 
learned by practice. 

Tools of almost every description may be purchased 
at reasonable prices, but the practice of making one's 



120 



HOME MECHANICS FOR AMATEUES 



own tools cannot be too strongly recommended. It 
affords a way out of many an emergency, and where 
time is not too valuable, a saving will be realized. A 
few bars of fine tool steel, a hammer, and a small anvil, 
are all that are required, aside from fire and water. 
The steel should be heated to a low red, and shaped 
with as little hammering as possible ; it may then be al- 
lowed to cool slowly, when it may be filed or ground to 




Fig. 119. 



Metal Lathe Tools. 



give it the required form. It may now be hardened by 
heating it to a cherry red and plunging it straight down 
into clean cool (not too cold) water. It should then be 
polished on two of its sides, when the temper may be 
drawn in the flame of an alcohol lamp or Bunsen gas 
burner; or, if these are not convenient, a heated bar of 
iron ma}^ be used instead, the tool being placed in con- 



HOME MECHANICS FOR AMATEURS 



121 



tact with it until the required color appears. This for 
tools to be used in turning steel, iron, and brass may be 
a straw color. For turning wood it may be softer. The 
main point to be observed in tempering a tool is to have 
it as hard as possible without danger of its being 
broken while in use. By a little experiment the ama- 
teur will be able to suit the temper of his tools to the 
work in hand. 




Pig. 122. Fig. 123. 

Metal Lathe Tools. 



In the engravings accompanying the present section 
a number of hand turning tools are shown, also a few 
tools for the slide rest. These tools are familiar to ma- 
chinists and may be w^ell known to many amateurs ; but 
we give them for the benefit of those who are unac- 
quainted with them and for the sake of completeness in 
this volume. 



122 



HOME MECHAmCS FOE AMATEUES 



No. 1, Fig. 119, is the ordinary diamond tool, 
made from a square bar of steel ground diag- 
onally so as to give it two similar cutting edges. 
This tool is perhaps more geuerallj' useful than 
any of the others. The manner of using it is 




shown in Fig. 127; it is placed on the tool rest 
and dexterously moved on the rest as a pivot, caus- 
ing the point to travel in a circular path along the 
metal in the lathe. Of course only a small distance is 
traveled over before the tool is moved alonsr on the 




■■■1^^ 



Fig. 125. Drill and Holder. 



rest. After a little experience it will be found that by 
exercising care a good job in plain turning may be 
done with the tool. 

No. 2, Fig. 120, shows a sharp Y-shaped tool which 
will be found useful for many purposes. No. 3 is a 
V-shaped tool for finishing screw threads. Nos. 4 and 



HOME MECHANICS FOR AMATEUES 123 

5 are round-nosed tools for concave surfaces. No. 6 
a square tool for turning convex and plane surfaces. 
The tool shown in No. 7 should be made right and left; 
it is useful in turning brass, ivory, hard wood, etc. No. 
8 is a separating tool. No. 9 is an inside tool, which 
should be made both right and left, and its point may 
be either round, V shaped or square. 

Fig. 128 shows the manner of holding an inside tool. 
No. 10 is a tool for making curved undercuts. No. 11 




Fig. 126. Boring with a Drill. 

is a representative of a large class of tools for duplicat- 
ing a given form. 

These figures represent a series of tools which may be 
varied infinitely to adapt them to different purposes. 
The user, if he is wide awake, is not long in discovering 
what angle to give the cutting edge, what shape to give 
the point, and what position to give the tool in relation 
to the work to be done. 



124 HOME MECHANICS FOR AMATEURS 



Having had experience with hand tools it requires 
only a little practice and observation to apply the same 
principles to slide rest tools. 

A few examples of this class of tools are given. No. 
12 is the ordinary diamond pointed tool, which shonld 
be made right and left. The cutting edge may have 
a more or less acute angle, according to the work to be 




Fig. 127. Using the Diamond Tool. 

done, and the inclined or front end of the tool may be 
slightly squared or rounded, according to the work. 
Fig. 13 is a separating tool, which is a little wider at 
the cutting edge than anywhere else, so that it will 
clear itself as it is forced into the work. 

For brass this tool should be beveled downward 
slightly. By giving the point the form shown in No. 
3 it Avill be adapted to screw cutting. 



HOME MECHANICS FOR AMATEUES 



125 



No. 14 shows an inside tool for the slide rest; its 
point may be modified according to the work to be 
done. No. 15 is a side tool for squaring the ends of 
shafts ; Nos. 16, 17, 18 and 19 represent tools for brass ; 
No. 10 is a round-nosed tool for brass, No. IT a V-shaped 
tool, No. 18 a screw thread tool, and No. 19 a side tool. 
In boring, whether the object is cored or not, it is de- 
sirable, where the hole is not too large, to take out the 
first cut with a drill. The drill and the drill holder 




Fig. 128. Method of Holding an Inside Tool. 



for the purpose is shown in Fig. 125, and the manner 
of using in Fig. 126. The drill holder, B, is held by 
a mortised post placed in the rest support. The slot of 
the drill holder is placed exactly opposite the tail cen- 
ter and made secure. The drill, which is fiat, is drilled 
to receive the tail center, and it is kept from turning 
by the holder, and is kept from lateral movement and 
chattering by a wrench, C, which is turned so as to 
bind the drill in the slot of the holder. 

The relative position of the tool and work is shown 



126 HOME MECHANICS FOR AMATEURS 

in Fig. 129. The upper cut shows the position for brass ; 
the next for iron and steel ; the third, the relative posi- 
tion of the engine rest tool and its work, and the fourth 
the position of the tool for soft metal and wood. 

In all of these cases the point of the tool is above 





Fig. 129. Position of Cutting Tools. 

the center of the work. In the matter of the adjustment 
of the tool, as well as in all other operations referred 
to, experiment is recommended as the best means of 
gaining valuable knowledge in the matter of turning 
metals. 

CHASING AND KNURLING 

Among the multitude of operations possible with a 
foot lathe perhaps none is more vexatious to the ama- 
teur than that of cutting a good screw thread, and no 
acquirement is more valuable than to be able to chase 
a screw thread easily and accurately. 

The ordinary chaser, No. 1, Fig. 130, is a simple 
tool which is easily made when one has the hubs for 
the dilferent sizes; but wanting these, we recommend 
the purchase of chasers. A blank for an outside chaser 
is shown in No. 2, and the hub used in cutting the 
teeth is represented in Fig. 131. The latter consists 



HOME MECHANICS FOE AMATEUES 



127 



of a piece of good steel having a thread of the desired 
pitch, which is traversed by spiral grooves to form 
cutting edges. This tool must have about the same 
temper as that of a tap. When used it is placed be- 
tween the lathe centers and revolved at a slow speed, 



No. 1. 





No. 2. 



Fig. 130. Chaser and Blank. 




Fig. 131. Hub. 





Fig. 132. Inside Chaser. 



Fig. 133. Blank for Chaser. 



while the end of the chaser blank is held against it, 
being at the same time supported by the tool rest. The 
hub should be oiled during the cutting process. After 
cutting, the tool is hardened and tempered, and ground 
on the elevated portion, which is the face, and smoothed 
on the back which slides upon the tool rest. 



128 



HOME MECHANICS FOR AMATEURS 



An inside chaser is shown in Fig. 132, the blank 
from Avhich it is made in Fig. 133. For convenience 
in cutting the teeth, the blank is bent at right angles; 
after cutting and before hardening it is straightened. 




Fig. 134. Starting a Thread. 

The manner of starting a thread for chasing is shown 
in Fig. 134, the tool used being shown. The rest is 
placed a short distance from the work, the tool is held 



Fig. 135. 



firmly upon it, and while the work revolves with a 
uniform speed the tool is moved dexterously so as to 
make a spiral line on the work, w^hich is nearly, if 
not exactly, of the same pitch as the thread to be cut. 



HOME MECHANICS FOR AMATEUES 



129 



If the operator is fortunate in the attempt, it will be 
a simple matter to start the chaser and move it along 
as indicated in Fig. 130. After a little practice it will 
in most cases be found an easy matter to chase threads 
Avithout first starting them with a pointed tool. It is 
much easier to chase an inside thread than an outside 
one. A chaser seldom goes wrong when w^orking on 
the inside. 




Fig. 136. Chasing a Thread. 

A method of chasing thimbles is shoAvn in Fig. 137. 
The threaded thimble which forms the guide screw is 
driven on the larger end of the tapering mandrel ; the 
thimble on which the thread is to be cut is placed on 
the smaller end of the mandrel. One arm of the forked 
tool has a vertical chisel edge, which engages the guide 

point which cuts 



screw; the other arm has a chasin 



130 HOME MECHANICS FOR AMATEURS 

the thread. The chisel edge is first brought into eu- 
gagement with the guide screw, the point is then 
quickly brought against the work with more or less 
pressure. After the thread is well started it may be 
finished with an ordinary chaser or with a pointed 
tool. 




Fig. 137. Chasing Thimbles. 

Fig. 138 shows a method of starting an inside thread. 
The chaser has a tracing edge that follows the guide 
screw projecting from the center of the chuck, and a 
cutting point that forms the thread. Fig. 139 shows 
the tool in detail. 

Threads cut by a chaser without some kind of a 
guide to start them are often more or less crooked or 
drunken. To correct such threads and in cutting large 
threads, the doctor, shown in Fig. 140, is sometimes 



HOME MECHANICS FOK AMATEUKS 



131 



employed. The follower opposite the chaser is moved 
lip by the thumbscrew as the thread deepens. 

The most expensive, and at the same time the most 
desirable, contrivance for chasing screw threads is 
shown in Fig. 141. A casting fitted to the lathe bed 
has two ears, wiiich are bored to receive the round 




Fig. 138. 




Fig. 139. Chasing Inside Threads, 

sliding rod carrying the tool holder and tracer. The 
tool holder is placed on the sliding rod between the two 
ears, and it carries a well-fitted screw, which bears 
against the horizontal bar supported by two square 
posts, which form a part of the main casting. This 
bar forms a guide wliicli may be adjusted within nar- 
row limits by the screw seen in the right hand post. 



132 



HOME MECHANICS YOU AMATEUES 



The lathe is provided with a face i^late having a long 
boss arranged to receive thimbles having leading- 
threads of different pitches cut on them. The tracing 
arm carries a thin tracing which engages the threaded 
thimbleSj and is capable of yielding to admit of mov- 
ing the cutting tool forward against the object being 
threaded ; but being well fitted to the mortise in the 
arm it cannot move laterally without carrying the 
sliding rod and all attached to it. The tracing tool is 
slotted to receive a pin which passes transversely 




Fig. 140. A Doctor for Cutting Large Threads. 

through the head of the tracing arm, and in the slot is 
placed a spiral spring which tends to throw the tracer 
forward. 

The operation of this device needs no special ex- 
planation. The arm that carries the cutting tool is 
moved forward until its adjusting screw strikes the 
horizontal guide bar; the tracing tool at the same 
time engages the leading screw and carries all forward. 
When the- tool has traveled as far as desirable it is 
drawn back and returned to its original position. With 
this tool threads may be cut on either cylindrical or 
tapering work. 



ILO^IK I^IECHANTCS YOU A]\rATEUES 133 




134 HOME MECHANICS FOR AMATEURS 

It is sometimes desirable to form spiral grooves in 
the face of a disk ; this may be accomplished in exactly 
the same manner as in the case of the cylindrical work. 
The method of doing it is illustrated by Fig. 142. 

Knurls of various patterns are shown in Fig. 143. 
These are employed in ^'beadingy' "milling," or knurl- 
ing the heads of screws, the handles of small tools, etc. 
The manner of using this tool is shown in Fig. 145. 



Fig. 142. Cutting Spiral Grooves. 

The knurl is placed between the forks of a holder and 
upon a pin that passes through the fork, and is held 
with considerable pressure against the work as it re- 
volves. 

The knurls shown in Fig. 144 are easily made. 
All that is required is a hub something like that 
shown in Fig. 131. This is placed between the centers 
of the lathe, and the knurl blank is brought in contact 
with it and allowed to revolve in a holder supported 



HOME MECHANICS FOR AMATEUES 



135 



by the tool rest. The straight blank is moved up and 
down until every part of the surface is cut in the same 
wav. The concave blanks cannot be moved, but the 




Fig. 143. Knurls. 




Fig. 144. Examples of Knurling. 




Fig. 145. Knurling. 



hub should fit the hollow of the face of the blank. The 
fancy knurl shown in Fig. 143 must be made by a die 
sinker. Fig. 144 represents examples of knurling 
done with knurls shown in the preceding figure. 



136 HOME MECHAXICS FOE xVMATEURS 

EOTAKiY CUTTEK8 

Tlie saving of files, time, materials and patience, by 
the employment of such rotary cutters as may be 
profitably used in connection Avith a foot lathe, can 
hardly be appreciated by one who has never attempted 
to use this class of tools. It is astonishing how much 
very hard labor may be saved by means of a small 



Fig. 146. Metal Circular Saw. 

circular saw like that shown in Fig. 146. This tool, 
like many of the others described in this section, 
can, in most instances, be purchased cheaper than it 
can be made, and the chances are in favor of its being 
a more perfect article. However, it is not so difficult 
to make as one might suppose. A piece of sheet steel 
may be chucked upon the face plate, or on a wooden 
block attached to the face plate, where it may be bored 
to fit the saw mandrel, and cut in circular form by 
means of a suitable hand tool. It may then be placed 
upon the mandrel and turned true, and it is well 
enough to make it a little thinner in the middle than 
at the periphery. 

There are several methods of forming the teeth on 
a circular saw. It nmy be spaced and filed, or it may 



HOME ]^IECHAXICS FOE AMATEUES 



137 



be knurled, as shown in Fi^-. 147^ and tlien filed, leaving 
every third or fourth tooth formed h\ tlie knurl; or 
it may, for some purposes, be knurled and not filed 




Fig. 14 



at all. Another wav of forming the teeth is to employ 
a hub, something like that used in making chasers, as 
shown in Fig. 148. The difference between this hub 
and the other one referred to, is that the thread has 
one straight side corresponding with the radial side of 




Fig. 148. Hub for Saw Making. 



138 



HOME MECHANICS FOE AMATEUES 



the tooth. The blank from wliich the saw is made is 
placed on a stud projecting from a handle made spe- 
cially for the purpose, and having* a rounded end which 
supports the edge of the blank, as the teeth are formed 
by the cutters on the hub. 




Fig. 149. Small Saw. 

The saw, after the teeth are formed, may be hardened 
and tempered by heating it slowly until it attains a 
cherry red, and plunging it straight down edgewise into 
cool, clean water. On removing it from the water 
it should be dried and cleaned with a piece of emery 
paper, and its temper drawn to a purple over a Bun- 
sen gas flame, over the flame of an alcohol lamp or 
over a hot plate of iron. The small saw shown in Fig. 
149 is easily made from a rod of fine steel. It is very 
useful for slitting sheet brass and tubes, slotting small 
shafts, nicking screws, etc. Being quite small it has 





Fig. 150. Mandrel. 



Fig. 151. Cutter. 



the advantage of having few teeth to keep in order, and 
it may be made harder than those of larger diameter. 
A series of them, varying in diameter from one-eighth 
to three-eighths of an inch, and varying considerably 
in thickness, will be found very convenient. 



HOME MECHAXICS FOR AMATEUKS 139 

Tliese cutlers or saws, witli tlie excci)tioii of the 
smaller one, may be used to the best advantage in con- 
nection with a saw table, like that shown in Fig. 153. 
This is a plane iron table having a longitudinal groove 
in its face to receive the guiding rib of the carriage, 
shown in Fig. 154, and a transverse groove running 
half way across, to receive a slitting gauge, as shown 
in Fig. 153. The table is supported by a standard or 
shank, which fits into the tool-rest socket. The saw 




Fig. 152. Making a Cutter. 

mandrel is supported between the centers of the lathe, 
and the saw projects more or less through a slot formed 
in the table. The gauge serves to guide the work to 
be slotted, and other kinds of work may be placed 
on or against the carriage, shown in Fig. 154. 

It is a very simple matter to arrange guiding pieces 
for cutting at any angle, and the saw table may be 
used for either metal or wood. The saws for wood 
differ from those used for metal; the latter are filed 
straight, the former diagonally or fleaming. Among 



140 HOME MECHAXICS YOV, AMATEUKS 

the many uses to wliicli metal saws may be applied we 
mention the slitting of sheet metals, splitting wires and 
rods, slotting and grooving, nicking screws, etc. Fig. 
155 shows a holder for receiving screws to be nicked. 
It is used in connection with the saw table, and is 
moved over the saw against the gange. 

To facilitate the removal of the screws the holder 
may be split longitudinally and hinged together. An- 
other method of nicking screws is illustrated b}^ Fig. 



Fig. 153. Saw Table. 

156. A simple lever, fulcrumed on a bar held by the 
tool post, is drilled and tapped in the end to receive 
the screw. After adjusting the tool all that is required 
is to insert the screw and press down the handle so 
as to bring the screw head into contact with the saw. 
Where a lathe is provided Avith an engine rest, the 
cutter shown in Fig. 151, mounted on the mandrel 
shown in Fig. 150, is very useful ; it is used by clamp- 
ing the work to the slide rest and moving it under the 
cutter bv working the slide rest screw. 



HOME MECHA^^CS FOPi AMATEURS 141 



To make a cutter of this kiud is more difficult than 
to make a saw, and to do it readily a milling machine 
would he recpiired. It may be done, however, on a 
plain foot lathe, by employing a V-shaped cutter and 




Fig. 154. Saw Carriage. 

using a holder (Fig. 152) haying an angular groove 
for receiving the cylinder on which the cutting edges 
are formed. The blank can be spaced with sufficient ac- 
curacy, by means of a fine pair of dividers, and after 
the first groove is cut there will be no difficulty in 
getting the rest sufficiently accurate, as a nib inserted 
in the side of the guide enters the first groove and all 
of the others in succession and regulates the spacing. 

One of the best applications of this tool is shown 
in the small engraving. In this case a table similar 
to the saw table before described is supported in a 
vertical position, and arranged at right angles with 




Fig. 155. Holder for Screws. 



the cutter mandrel. The mandrel is of tlie same diam- 
eter as the cutter, and serves as a guide to the pattern 
which carries the work to be operated upon. The prin- 
cipal use of this contrivance is to shape the edges of 



142 



HOME MECHANICS FOE AMATEURS 



curved or irregular metal work. The castiug to be 
finished is fastened — by cement if small, and by clamps, 
if large — to a pattern having exactly the shape required 
in the finished work. 




Fig. 156. Nicking Screws. 

By moving the pattern in contact with the table and 
the mandrel, while the latter revolves, the edges of 
the work will be shaped and finished at the same time. 
By substituting a conical cutter for a cylindrical one, 
the work may be beveled; by using both, the edge may 
be made smooth and square, while the corner is beveled. 

The tool shown in Fig. 157 might properly be called 
a barrel saw. It is made by drilling in the end of a 




Fig. 157. Barrel Saw. 

steel rod and forming the teeth with a file. To avoid 
cracking in tempering a small hole should be drilled 
through the side near the bottom of the larger hole. 
To insure the free working of the tool it should be 
turned so that its cutting edge will be rather thicker 
than the portion b(^hin(l it. This tool should be made 
in various sizes. 



HOME MECHANICS FOR AMATEUES 



143 



EASILY MADE SLIDE REST 

While the most of the Avork to be done on the foot 
lathe may be accomplished as expeditiously and quite 
as well without a slide rest as with it, yet there are 
some operations that are greatly facilitated by means 
of this tool. Boring, for example — a very difficult thing 
to do with hand tools — may be done quickly and ac- 
curately by using a slide rest. In gear cutting — de- 
scribed in another part of this section — a slide rest is 
essential. 




Fig. 158. The Complete Slide Rest. 

In the case of tliis tool, as well as others previously 
described, the purchase of a well-made article is recom- 
mended. Yet, if one has time and feels so inclined, lie 
may make a really efficient slide rest with no other 
tools than his lathe and ordinarj^ turning tools. Figs. 
158 to 160 inclusive represent a slide rest that may be 
made in this way, Fig. 158 being a jDerspective view, 
and Figs. 159 and 1(>0 respectively longitudinal and 
transverse sections of the tool carriage. 



144 



HOME MECHAXICS FOK AMATEURS 



The T-shaped casting, A, has a h)ngitudinal slot, 
which is made T-shaped in cross section to receive the 
head of the bolt that confines it in position upon the 
plate fitted to the lathe bed. The vertical ears at op- 
posite ends of the casting are bored to receive the ends 
of the rods, B, upon which the tool carriage, C, slides. 

The first operation in making the slide rest is to 
make one side of the casting, C, perfectly plane. It is 




Fig. 159. Longitudinal Section of Slide Rest. 




Fig. 160. Transverse Section of Slide Rest. 

then chucked in the lathe with the plane side next 
the face plate. Three holes are bored through it, two 
for the rods, B, and a smaller one for the screw, G. 
It is then chucked on an angle plate, so that the holes 
for the rods, B, are equally distant from the center line 
of the lathe, and the hole for the rod D, is bored very 
carefully to insure the i)arallelism of its sides. The 
casting. A, is now placed upon a plane surface, and the 



HOME MECHANICS FOR A.AIATEURS 145 

castin<>-, C, is clamped to the ear at one of its ends, and 
adjusted so that a line drawn through the center of 
the holes is exactly parallel with the bottom of the 
casting. The casting, C, is used in this manner as a 
template for drilling both of the ears for the reception 
of the rods B. It will be necessary to exercise great 
care in drilling these holes, as it is of vital importance 
to have the rods, B, perfectly parallel. 

The casting, C, may now be tapped to receive the 
scrcAV, G, and the tool-carrying bar, D, may be fitted 
to its place, and turned down and threaded to receive 
the internally threaded boss of the wheel, E. This 
boss is fitted to the base of the casting, C, and is grooved 
circumferentially to receive a split ring, F, the latter 
being drilled to receive the ends of three screws that 
project through the casting into it and prevent the 
boss of the wheel, E, from moving lengthwise of the 
hole, while the arrangement permits of the free rotation 
of the wheel. The bar, D, has a head which is drilled 
vertically to receive the tool post, and is provided 
with a heavy feather at the top, which is received by 
the slot formed by sawing into the upper portion of the 
casting, C. To render the bearing of the bar, D, some- 
what adjustable, two screws pass through the casting- 
above the feather. The tool post is of the usual de- 
scription, having a loose collar above the head of the 
bar, D, and a nut below it. The mortise for receiving 
the tool extends a little below the loose collar, so that 
when the tool is clamped the post and ring will also 
be clamped. A slot is cut through the bottom of the 
casting, C, into each of the guide rod holes, to permit 
of adjustment in case of wear by means of the screws 
which pass transversely through the slot. The ends of 



14G HOME MECHANICS FOR AMATEUES 

the rods, B, are fastened by a similar device. The screw, 
G, is prevented from end motion by a shoulder on the 
outside of the ear at the crank end, and a collar on 
the inside. The rods, B and D, may be made of steel 
or of cold rolled iron; the latter Avill be true enough 
without turning. The casting may be either of brass 
or iron ; a good quality of iron will perhaps prove the 
most satisfactorv. The slots may be cut with the 




Fig. 161. Boring Attachment. 



saws described in a former article. The tools to be 
used with the slide rest have also been previously 
described. 

In Fig. 161 is represented a boring device which will 
be readily understood without special description. The 
casting, A, is fitted to the tool rest socket and provided 
with a sliding bar, B, which is like the bar, D, in the 
slide rest above described, excepting that its back end 



HOME MECHANICS FOR AMATEURS 147 

is rounded and provided with a pin which slides in the 
slotted arm attached to the tail spindle of the lathe by 
which it is moved^ instead of havin^^' a moving device of 
its own. Witli this tool, boring and some kinds of out- 
side turning may be done. It is less expensive than 
the slide rest and ansAvers a good purpose. It is prob- 
able that in making both these tools the services of a 
mechanic provided with a planer or shaper will be re- 
quired. 



INDEX PLATES FOR GEAR CUTTING 

There are many amateurs who would make their 
own gear wheels were it not for the expense of pur- 
chasing or the trouble of dividing and drilling the 
index plate, which is the principal item in the ap- 
paratus required in cutting small gears. 

Of course an index plate may be purchased, but the 
money thus laid out would go a long way toward pay- 
ing for cutting all the gears that would ever be re- 
quired by most amateurs. 

It is admitted that it is difficult to obtain absolute 
accuracy by ordinary methods, but the plans here sug- 
gested will probably give as nearly perfect results as 
can be obtained without copying another index plate 
or using a dividing engine. 

The index plate, before being divided, should be 
nicely turned and fitted to the place it Avill occupy on 
the lathe. This Avill generally l)e on the larger side of 
the cone pulley. 

Two methods of graduating an index plate are il- 
lustrated by the accompanying engravings. One con- 



148 HOME MECHAXICS FOll AMATEURS 

sists iu locating the holes by using paper scales whieli 
are printed from engine divided plates, and are, there- 
fore, very nearh^ accurate. The other consists in divid- 
ing the plate b^' aid of a large paper disk graduated by 
hand. 

For the most of purposes four rows of holes will 
answer. The best nund^n' of holes for the different 
rows is as folloAvs: 240, 200, 144, 132. 240 can be 
divided as follows: 120, 60, 48, 40, 30, 20, 15, 12, 6. 
With 200 divisions: 100, 50, 40, 25, 20, 10 and 5 may 
be made. 144 divides into 72, 48, 30, 24, 18, 16, 12, 
9, 8, 6. 132 into 66, 44, 33, 22, 11. 

The best method of dividing an index plate of which 
the T^^iter has any knowledge, aside from duplicating 
another, or using a dividing engine, is shown on the 
next page. A wooden block. A, is attached to the face 
plate of the lathe by means of screws, and turned down 
truly on the face and upon the edge. A portion of the 
edge is turned to a suitable diameter for receiving a 
certain length of ])aper scale, C. The other portion of 
the edge is pressed by a brake shoe, F, which is kept 
up by a screw in the standard, D. An index, E, is 
slotted and secured to the top of the standard, D, by 
a screw. To the face of the block. A, is secured the 
index plate, B, and in front of the plate there is a drill 
support which takes the place (^f the ordinary tool rest. 
The drill is capable of longitudinal as well as rotary 
motion in its support; it is driven by a belt from the 
drive wheel of the lathe, and is pushed forward a lim- 
ited distance by tin* handle swiveled to the end of the 
drill spindle, Tlie size of the drill will be gov(^rned 
altogether l)y tlie si/.e (jf thi^ plale; l)ut in any case 
it should be as large as possibles always bearing in 



HOME MECHAXICS FOli AMATEUES 



149 



iiiiud tlial the space between tlie holes slionid be of suf- 
ficient width to insure tlie rcMinired stren<;tli. 

That portion of the wooden bloclv, A, which receives 
tlie paper scale, C, is carefully turned so as to permit 
the ends of the scale to abut; the scale being very care- 
fullv cnt so that its ends will join accurately and render 




Fig. 162. Method of Graduating Index Plates. 



the graduations of the scale uniform throughout. The 
scale is best attached to the block by means of paper 
tacks or small screws. For the greatest number of 
graduations given above, a two foot paper scale, or 
two pieces of shorter scales, will be required. The 
inches should be divided into tenths. The block should 
be 7.64 inches in diameter where it is surrounded by 



150 HOME MECHANICS FOR AMATEUES 

the scale. The diameter of that part engaged by the 
brake shoe is not limited to any particular size. 

It is obvious that for drilling 240 holes every mark 
on the scale must be brouglit opposite the index, E, 
and stopped by means of the brake, F, while a hole is 
drilled. After drilling tliis row of holes, the row con- 
taining 144 holes should be drilled, leaving a space 
between it and the 240 row^ for the 200 row. For the 
144 row the operation is the same as that already 
described, except that a scale divided into twelfths is 
used, and alternate graduations only are noticed. The 
intermediate ones should be crossed out, so that the 
scale will really be a scale of inches divided into sixths. 
For the 132 row the block is turned down to 7 inches 
diameter, and the scale last used is shortened to 22 
inches and again applied to the block and used as 
before. 

After completing these rows of holes the drill is 
moved to the space between the first and second row^s, 
the block is turned down to 6.36 inches, and 20 inches 
of the paper scale first used (inches divided into 
tenths) is employed. Every graduation on the paper 
scale is used in this case as in the first instance. This 
gives 200 divisions. 

The paper scales recommended for this purpose are 
those used by engineers and draughtsmen. They may 
be obtained for a few cents from any dealer in mathe- 
matical instruments. 

In Fig. 163 the larger circle represents a disk of 
paper which is carefully divided into large spaces by 
means of ordinary dividers, and the large spaces are 
subdivided in the same way. 

In the center of the paper disk is placed the plate to 



HOME MECHAI^ICS FOR AMATEtTES 



151 



be divided, and from the center of the plate rises a 
stud, to which is accurately fitted the sleeve attached 
to the end of the radius bar. The radius bar extends 
beyond the outer circle on the paper disk, and carries 
an adjustable sleeve, to which is accurately fitted a 




Fig. 163. Index Plates for Gear Cutting. 

drill which may be rotated by means of a small drill 
stock. The slecA^e that forms the bearing of the radius 
bar is shown in detail in the lower left hand corner of 
the engraving, and the sleeve that receives the drill is 
shown in the opjiosite corner. 

While drilling, the radius bar is held in place by a 



152 HOME MECHAXICS YOR A]\rATEUES 

wcjolit or by means of a clamp. After drilling each liole 
the bar is moved forward one space and secnred by the 
weight or clamp. When one row of holes is completed, 
the sleeve which gnides the drill is moved toward the 
center of the disk, and the operation of drilling is car- 
ried on as before. By this method whatever errors may 
exist in the gradnations on the paper disk are greatly 
reduced in the index plate, and the plate produced will 
l)e accurate enough for most purposes if the work on 
the paper disk has been carefully done. The smallest 
plate should be at least three-sixteenths of an inch 
thick, and the lioles should not be drilled quite through. 
Either iron or brass may be used for the disk. The lat- 
ter works the easiest and will answer every purpose. 

GEAR CUTTING APPARATUS 

The index plate, A, is attached to the larger of the 
pulleys on the mandrel of the lathe by means of three 
or four screws, and the stop, C, provided with a point 
well fitted to the holes in the plate, is held in position 
on the bed plate, B, by a screw iDassing through a slot in 
the foot into the bed piece. The stop, C, is capable of 
springing sufficiently to admit of withdrawing the pin 
from the hole in the plate, and it is strong enough to 
hold the plate without vibration. Two standards, G, 
mounted on the plate, B, support pulleys over which 
the driving belt runs. The gear cutter head consists of 
a casting, D, fitted to the tool post of the slide rest, 
and the mandrel, E, provided Avith a pulley and 
mounted on carefully fitted centers in the casting. The 
casting, D, has upon opposite sides, near the upper end, 
ears (as shown in Fig. 165) for receiving the pulleys. 



HOME MECHAXICS FOR AMATEL'IJS 153 




o 



154: HOME MECHAXICS FOR AMATEURS 

(/ h, which ,i»nide the driviug belt, so that the cutter 
may be removed across the face of the wheel being cut 
Avithout chauging the tension of the belt. The ex- 
treme end of the loop formed by the belt is supported 




Fig. 165. Detail of Gear Cutter. 

by the pulley, H, mounted on a standard rising from 
the lathe bed. The standard may be placed far enough 
from the slide rest to admit of putting the tail stock 
between it and the slide rest in case it should be neces- 
sary to use the tail stock for supporting the work. 




Detail of Pulleys. 



JF 



Fig. 166. 



P 
I 



Cutters. 



HOME MECHANICS FOR AMATEURS 155 

The mandrel, E, is provided with a eolhir and a nut 
for damping the cutter, F. It will be noticed that the 
cutter comes exactly opposite the line of the lathe cen- 
ters, and that it occupies about the same position, in 
relation to the tool post, that the point of an ordinary 
turning tool does. The cutter, F, is sho^yn in Fig. !()(>, 
enlarged. The upper yicAy represents the side, the 
loAyer view the edge of the cutter. It has but a single 
tooth and is adapted to brass and similar alloys only. 
It may be sharpened by grinding. When iron or steel 
is to be cut the cutter should haye several cutting edges, 
and the mandrel, E, should have a larger pulley, as 
more power will be required and the speed must be 
slower. By setting the slide rest at an angle bevel 
gears may be cut. 

HINTS ON MODEL MAKING 

It is a simple matter for an experienced instrument 
maker or machinist to produce a fine model with turned 
shafts, cut gearing, true pulleys, and smooth working 
cams, but it is quite another thing for an inventor, 
without tools or materials, to embody his ideas in a 
working model even though he may have a mechanical 
taste. 

It is fair to suppose that every mechanical inventor 
in these days of cheap machinery possesses some sort 
of a lathe, as these indispensable machines are now 
made for prices within the reach of almost any one. 

It is quite evident, from an inspection of the models 
of the Patent Office, that most inventors who under- 
take to make their own models expend a great deal of 
labor without corresponding results. In the matter of 



156 



HOME MECHAXTCS FOT^ AMATEUES 



^iicai-ini;, for instance, one w'\]\ y\]\\t{]v liis ^^■luH*ls iu 
wood, another will borrow liis <»earini> from some de- 
funct clock, while still another will purchase ready- 
made wheels from one of our well known firms makin^i,' 
a business of furnishing parts of models. 

Of the three methods of obtaining the gearing the 
latter is undoubtedly the best, as all that is necessary 
to l)e done, in case of the cast gear wheels, is to bore 
them and file up the teeth, and as the cut gear wheels 




Fig. 167. Friction Gearing 

are generally bored, the shaft may be fitted without 
further work on the wheels. It is, however, seldom 
absolutely necessary to use toothed gearing, as rotary 
motion may be readily transferred by suitable friction 
wheels or by grooved or sprocket wheels and a round 
belt. 

Fig. 167 shows a form of friction gearing which is 
both simple and effective. The larger wheel is simply 
a disk of sheet brass having rounded edges, and boss 



HOME MECHANICS FOll AMATEUl^S 



157 



spim or soldered on, and a smaller wheel consists of two 
swaged disks of steel having their convex faces sepa- 
rated by a metal washer a little thinner than the large 
wheel. These three members are secured to a common 
l)oss by spinning the end of the boss partly over one of 
the disks, as shown in the sectional view, No. 2. This 
form of friction gearing is noiseless and runs strong 
enough for the requirements of almost an}^ model. 

Figs. 168 and 169 show a form of sprocket wheel 




Fig. 168. 



Fig. 169. 



Sprocket Wheels. 



which is readily made and is almost as positive in its 
action as gearing. In this case the two wheels are 
alike; they consist of disks of sheet metal nicked to a 
uniform depth from the edge, and the arms thus formed 
are bent alternately in opposite directions, forming a 
groove for receiving the round belt used in transferring 
motion from one wheel to the other. It is evident that 
a belt cannot slip on a wheel of this construction. 

Fig. 170 shows a form of friction gearing for trans- 
ferring motion at right angles, and for imparting a 
variable speed to a shaft from another shaft running at 



158 HOME MECHANICS FOli AMATEUES 

a uniform rate. The large wheel in this instance is 
merely a plane disk of metal mounted in the manner 
already described. The smaller wheel is a grooved 
metal pulley surrounded by an elastic rubber ring. 
This is pressed with more or less force against the me- 
tallic disk, and its speed may be varied by moving it 
toward or away from the axis of the disk. 

As to the matter of irregular motion usually im- 
parted by cams, it is difficult to make a cam in the ordi- 




FiG. 170. Transferring Motion at Right Angles. 

nary way with the milling machine, and there appears 
no very simple way of cutting them from solid castings. 
There is, however, a simple way of building them up 
from readily obtained materials. 

Fig. 171 shows a cam consisting of a cylinder of brass 
or a short section of brass tubing provided with two 
heads and mounted on a shaft. The cam groove is laid 
out on this surface, and two parallel pieces of square 
brass wire are soldered to the surface of the cylinder, 
or fastened by means of screws. They are placed uni- 
forndy distant tliroughout tlie entire circumference of 
the cylinder. 



HOME MECHANICS FOR AMATEURS 



159 



Fig. 172 shows a cam built up iu tlie same way on the 
face of a dislv. 

As to shafts, the model maker may save himself much 
labor and expense by nsing l^tnl)bs' steel for small 
shafts, and cold rolled iron for larger ones. Either 
the steel or iron may be bought in one and three foot 
lengths. 

Almost anything in the way of parts of models may 
be purchased ready for use, so that all the inventor need 
do is to combine them and mount them on a suitable 





Fig. 171. Drum Cam. 



Fig. 172. Disk Cam. 



frame ; but even so simple a matter as a Avooden frame 
for a model sometime proves troublesome. 

The small tenons and mortises are difficult to make, 
and the frame to be strong enough to bear handling 
must be made so heavy as to be entirely out of propor- 
tion. A simple and easy method of securing the joints 
of small frames is to clamp the parts in the position 
they are to occupy in relation to each other, and then 
drill, with a sharp twist drill, two holes through one 
piece from side to side and into the end of the abutting 
piece, then inserting two hard wood pins, having previ- 
ously coated them with glue. This makes a joint far 
stronger than the xuortise and tenon, and it is very 
quickly done. 



160 



IIO.AIE MECHANICS FOE. AMATEURS 



METAL SPINNING 

The operation of spinnin.i>' metals, irltliougli exceed- 
iii<ilv simple and capable of beino- practiced to advan- 
tage in almost every shop, and also by the amateur me- 
chanic upon the foot lathe, is not generally understood. 
One reason for this is that the artisans who follow this 




Fig. 173. Metal Spinning. 

branch of mechanics as a business usually conduct it 
under locked doors, and it is with considerable diffi- 
culty that the amateur in search of information on this 
and kindred subjects can obtain (mtrance to one of 
these establishments. The reason of this secrecy is 
plain enough, as the ^'kink'' or ''wrinkle/' or, in plain 



HOME MECHANICS FOR AMATEURS 101 

English, the knowledge required to do the mechanical 
part of spinning is so slight that secrecy is the only 
protection. 

The tools required are few. They consist of a lathe ; 
a form or mould on which to shape the article; a tool 
rest with a series of holes for receiving a pin to keep the 



Fig. 174. 




Fig. it; 



Spinning Tools. 



tool from slipping, and a few spinning tools or burnish- 
ers of different sizes and shapes. 

The lathe the amateur is supposed to possess; the 
tool rest he may easily make ; and the only other addi- 
tion to the lathe will be a back center of the form shown 
in Fig. 174. This form of center answers as a step to 
the work holder, and will bear considerable pressure 
without undue friction. 

The tools required are shown in Fig. 175. These are 



162 HOME MECHANICS EOK AMATEUliS 



simplj^ hard steel burnishers of the form shown^ and 
varying in size with the size and kind of work to be 
done. The size given in the engraving is about right for 
amateur work on a foot lathe. No. 1 shows in two 




Fig. 176. 



Fig, 177. 



The Forms in the Lathe. 




Fig. 178. The Use of the Bolt 



views a ball tool. No. 2 shows both side and edge views 
of a curved tooL No. 3 shows a plain round burnisher. 
In some instances it ma}^ be necessary to make tools of 
different forms. The operator will be guided in the 
selection of his tools by the particular work in hand, 



HOME MECHANICS FOR AMATEUES 



1G3 



and practice will brinji new suggestions as to the tools 
and the manner of using them. 

The materials generally used in spinning are brass, 
copper, zinc, britannia metal and lead. All of these 
mav be worked on the foot lathe, but perhaps the ama- 





FiG. 179. Fig. 180. 

The Movement of the Tool. 



teur will derive the most satisfaction at first by using 
britannia metal, as it works easily and does not require 
annealing. Articles in this metal also present a hand- 
some appearance when done, whether simply polished 




Fig. 181. Spinning without a Form. 



Fig. 182. Spinning a Ring. 



or plated. Zinc must be spun quite hot. Articles of 
brass, if of considerable depth, must be annealed when 
partly done. 



164 HOME MECHANICS FOR AMATEUES 



The form on which the metal is spun may be either 
hard or soft wood or metal. A good close grained pine 
answers as well as anything for most purposes, and i^ 
very readily turned to the required form. It may be 
attached to the face plate, B, and the disk to be spun 
may he held against it at first by a hard wood or metal 
piece, C, as shown in Figs. 176 and 177, which is forced 
against the disk by the tail center. After the spinning 
is a little advanced, a cup-shaped holder is applied, as 



shown in dotted lines in Fig. 1 



I i. 



Sometimes the 





Fig. 183. Concave Reflector. 



Fig. 184. Cup. 



holder is secured by a bolt that runs through both it 
and the form or mould, as shown at D, Fig. 178. In 
some cases a little rosin is applied to the form to in- 
crease the friction, but this is rarely necessary. The 
motion of the lathe should be quite rapid, and the disk 
should receive a coating of grease (lard or heavy oil) 
before applying the burnisher. A very strong solution 
of soap may be used instead of oil. The position of the 
Avorkman and the manner of holding the tool may be 
seen in Fig. 173. It will be noticed that the pin in the 
tool rest serves as a fulcrum for the tool, which must 
be brought with considerable pressure against the sur- 



HOME MECHANICS FOE AMATEUES 



1G5 



face of the disk. Tliis pin is moved forward from lime 
to time as the work advances. The movement of the 
tool may be seen in Figs. 179 and 180. The shape taken 
by the metal in front of the tool will also be seen. In 
swinging the tool toward the form it is moved in the 





Fig. 186. Ball 




Fig. 185. Vase. 



Fig. 187. Pitcher. 



direction of the arrow as shown in Fig. 179, and it is 
carried back as shown in Fig. 180. This last operation 
is very essential to the proper fitting of the mould, and 
it also thickens the metal. Too much should not be 
attempted at a time. A succession of quick movements, 
as indicated in Figs. 179 and 180, under a moderate 
pressure is much better than to do a great deal of exe- 
cution at a single stroke. Should the metal tend to 



160 



HOME MECHxVXlCS FOR AMATEURS 



vibrate or buckle, a piece of wood may be applied to the 
back with the left hand, as shown in Fig. 178. 

The method of spinning a cup or pot without a form 
is illustrated in Fig. 181. Here the metal is supported 
by a plain cylindrical mandrel, and is first spun into 




Fig. 188. Card Receiver 



Fig. 189. 



the form indicated by the dotted lines, and then bring- 
ing the burnisher on the return stroke only to the 
shoulder Avhich forms the larger part of the ves- 
sel. For small work on the foot lathe the handles 
of the tools need not be as long as represented, 
in Fig. 173. The length commonly employed for wood 
turning tools will answer. 

To spin a ring, a mandrel like that shown in Fig. 



HOME :\IECHAXTCS FOE AMATEURS 



167 



182 will he rcMiuired. A plain flat ring placed between 
the shoulders of the mandrel is pressed upon by the 
roller seen above the mandrel until the ring assumes 
the desired form. Napkin rings are made in this way. 




Fig. 191. Vase. 



Fig. 183 shoAvs a concave reflector. Fig. 184 represents 
a simple cup formed of two pieces. Fig. 185 represents 
a small vase made of three pieces, the smaller end of 
the upper or conical part and the upper portion of the 



168 HOME MECHANICS FOR xVMATEUES 

base piece being soldered in a spherical connecting 
piece. The two halves of the ball, Fig. 186, are made 
upon the same form. The edges are beveled and sol- 
dered together. The pitcher, Fig. 187, is made of five 
spun pieces, a short cast and turned piece that unites 
it to its base, and a handle made of square wire. The 
card receiver. Fig. 188, has a spun top and base, and 
a cast standard. The vase. Fig. 189, consists of four 
spun pieces and three legs of square wire, uniting the 
body with the base. Fig. 190 shows a base for a mag- 
netic needle or other small apparatus. Fig. 191 repre- 
sents a vase composed of seven spun pieces and two 
handles of square wire. More complex examples of 
work done by the process of spinning might be fur- 
nished. The ones given are undoubtedly sufficient to 
enable the amateur to get an idea of the endless variety 
of articles that may be made by this simple and easily 
acquired art. 



PART lY. 

MODEL ENGINES AND BOILERS 

A HOiME-MADE STEAM ENGINE 

A STEAM ENGINE carefully made is a piece 
of mechanism to be proud of, no matter 
what its particular design may be. A 
double-acting engine of good proportion, 
with a bored cylinder and forged crank and crank 
shaft, and other parts made in keeping, is, of 
course, the better form of steam engine to make, but, 
as we are presuming that not every amateur has the 
facilities for building such an engine, a description of 
a simple single-acting engine which could be made by 
any boy handy with tools is given. It can be made with 
an ordinary light foot lathe, as no boring is required, 
nor is there any turning to be done that does not come 
within the range of such a lathe. 

A view of the engine and the boiler and engine is 
given, and also a sectional view showing the construc- 
tion of the valve and valve-operating cam, and the 
steam passages in the base. 

The cylinder consists of a piece, A^ of mandrel-drawn 
steel tubing (which needs no boring) 2^ inches long 
and i inch internal diameter. The thickness of the 
metal forming the tube is tV inch. This piece of tub- 
ing is fitted to a boss, a, about ^ inch high, formed 
on the brass block, near one end. This block is 1^ 
inches long and ^ inch thick, and is provided with 
lugs for receiving screws, by which it is attached to 
the base plate. In this block are formed the steam 

[169] 



170 HO]\rE ]\[ECHAXICS FOR AMATEUES 

passages, h c, and valve clianiber. This hole drilled 
from the front backward and forming the passage, h, 
receives the steam snpply pipe, B. A hole is drilled 
from the rear end of the block forward to a point 
about opposite the center of the cylinder, forming with 
the hole, d, the steam duct, c d. Near the rear end of 
the block is drilled a re inch hole, from beneath, which 
forms the valve seat, r, just beyond the passage, h. A 
16" inch hole is started at the valve seat, e, and con- 
tinued to the top of the block. This smaller hole is 
counter-bored from the top with a yV inch drill, leav- 
ing the valve chamber. The counter-bored portion of 
this hole receives the plug, /, which is bored longitudi- 
nally to receive the valve stem, g, of the conical valve, 
e'. The valve stem is about 3j inches long, and is 
provided with the adjustable collar, //, between which 
and the plug, /. is placed a spiral spring which tends 
to keep the valve normally closed. The steam pas- 
sages, h and r% are closed with screw plugs, as shown. 

To the steel tube which forms the cylinder is fitted a 
piston of cast iron. It is about IJ inches long and is 
packed by the steam or water contained in the grooves 
in the piston. The upper end of the piston is slotted 
to receive the loAver end of the connecting rod, which 
is pivoted therein upon a ^-inch pin passing through 
the piston and lower end of the connecting rod, as 
shown in dotted lines in the sectional view. 

The brass block which supports the cylinder has 
lugs on opposite sides receiving screws which pass 
through them into the base plate. This plate is 4 
inches wide, 5 inches long and ^ inch thick. At the 
rear of the valve chamber is a post formed of a 4-inch 
square brass rod 4f inches long, secured to the base 



HOME :\IECITAXICS Ton A]\rATEUTJS 



171 



plate l)Y ii screw passiiii;- upward iliPiMiuli i\u^ plate 
into tlie end of the post. A similar post is placed near 
the rear end of tlie base plate. The ends of the posts 
are squared in the lathe. Botli posts are bored trans- 



^ 


i 


la ^jl'^^^liKi' m ^ ^j^^ 






\ 

- \ 




m 



Fig. 192. Simple Steam Engine. 

verselA^ near the top to receive the shaft, which is ^ 
inch in diameter and 5 inches long. The space be- 
tween the posts is 2 inches, and the distance between 
the shaft and base plate is 3J inches. On the shaft, 
between the posts, is placed the iron flv- wheel, Avhich in 



172 HOME MECHAXICS FOR AMATEURS 

the presenl case cousists of an olH valve wheel 4^ inches 
in diameter, bushed to fit the shaft and fastened with 
a set screw. 

The end of the shaft which projects beyond the post 
over the cylinder carries a ^-incli crank on which is 
placed a connecting rod. This rod measures If inches 
between the centers of the holes for the crank pin and 
the pin in the piston. 

In the side of the cylinder are drilled three -^j inch 
holes in a horizontal line, and close together to form 
the exhaust port of the engine, which is entirely un- 
covered by the piston when it is in the position shown 
in the engraving. The exhaust remains open for about 
a quarter of the revolution. This port is left exposed 
for clearness, but it may be covered by a hollow ring 
which encircles the cylinder and receives an exhaust 
pipe. 

On the left shaft is placed a cam, in w^hose boss 
there is a circumferential groove, and upon the upper 
end of the valve stem is placed a fork, the upper ends 
of which slide in the groove in the boss of the cam. A 
stud in::Grted in the fork has upon it a roller which 
rolls on the higher part of the cam and opens the valve 
at the proper instant. This cam opens the valve just 
before the piston reaches the lower limit of its stroke, 
and allows the vah^e to close just before the exhaust is 
opened by the piston. 

The boiler of this engine consists of a copper float to 
be found in the market, made by an electrolytic de- 
posit of copper. Such a float forms a seamless boiler 
capable of withstanding a great pressure, say 100 
pounds. The boiler is mounted in a tripod made of 
band iron and is furnished with a safety valve | inch 



HOME MECHANICS FOK AMATEUES 



173 



in diameter, the lever of which is about 2 inches lon<», 
and graduated and weighted so that it will blow off at 
35 pounds, thus insuring perfect safety. (The ordinary 
copper float is not recommended.) A brass steam pipe, 
1 inch internal diameter, is screwed into the safety 




Fig. 193. Simple Steam Engine. 



valve casing below the valve sat, and has at its end a 
miniature angle valve which is connected to the engine 
])y th(^ inclined pipe, and by elbow and nipple which 
extends into tlie base. As the angle valve is a trouble- 
some piece of work, an ordinary stop cock is recom- 



174 



HOME MECHANICS FOR AMATEURS 



mended in its stead. It should be placed in the in- 
clined pipe. 

The best burner for this boiler is an Argand gas 
Bunsen burner like that shown. Of course an alcohol 
lamp Avill answer, but it is not as safe as the gas 
burner. 




e' c h 

Fig. 194. Sectional View of Engine. 



Both engine and boiler should be mounted on a 
suitable base board. 

The engine is capable of making a thousand or 
twi^lve hundred revolutions pea* minute. It must be 
well balanced for this speed. 



HOME MECHANICS FOR AMATEURS 175 

• The boiler is filled when cold through the safety 
valve opening by means of a funnel having a slim cor- 
rugated tube. The boiler should be about two-thirds 
full of water at the start. 

It is obvious a larger engine could be made on the 
same principle; but the front support for the shaft 
should be made A-shaped and placed next to the 
crank, and the cam should be placed between the sup- 
port and the fly-wheel ; the shaft support Avould then 
extend over the cylinder-base. 

A SAFE WAY TO KUN A SMALL ENGINE 

Almost every youth at some time in his life has 
coveted a steam engine, or some other motor having 
energy and ability to move of itself and to impart mo- 
tion to other machines, but through fear of fire from 
the lamp used to generate steam, or anticipating pos- 
sible explosions, has been obliged to forego the pleasure 
of being a boy engineer, and seek amusement in other 
directions. Ever}^ boy can own a steam engine, since 
one can be purchased for 50 cents, |1, |2 or more, and 
the engine can be run with safety by means of com- 
pressed air. Any engine that will run by steam will 
run equally well with compressed air. 

Rut how is the compressed air to be furnished and 
stored for use? There are very few families without 
bicycles, and every bicycle requires a pump for in- 
flating the tire; why not use the same pump to com- 
press air for an engine? The boiler constitutes a small 
reservoir, and an auxiliary reservoir may be connected 
Avith the boiler l)y means of a small rubber tube. The 
auxiliary reservoir may consist of a piece of strong 



176 HOME MECHAmCS FOE AMATEURS 

3-inch galvanized iron leader, with caps soldered on the 
ends, with a small tube inserted at any convenient 
point to receive a bicycle valve, and another small 
tube to receive the piece of small rubber tubing which 
forms the connection between the reservoir and the 
engine or the boiler belonging to the engine. 

This boiler and reservoir when pumped up as much 
as possible by ordinary exertion, will run the engine 
while driving the boat for about 15 minutes. The caps 
to the reservoir mentioned are made conical so that 
the reservoir may be drawn in the water after the boat, 
the connecting rubber tube forming the hawser for tow- 
ing the reservoir. 

If it is desired to run a stationary engine with com- 
pressed air, the reservoir may consist of a tin can. A 
1-gallon varnish can ansAvers very well, but it can be 
forced out of shape and even exploded unless it is en- 
cased in a strong wooden box fitting it closely and put 
together with screws. 

A MINIATURE CALORIC ENGINE 

The hot air engine is not a very recent invention. A 
number of engines of this class, of different sizes, were 
devised and used in the early part of the present cen- 
tury, and in the latter part of the last century there 
were in existence engines constructed to be operated by 
the expansion of air. 

Nothing in the way of a motor, aside from a wind- 
mill or water wheel, can be more simple than this, and 
it is a pity that it is not capable of more general ap- 
plication. Motors of this kind have been used to some 
extent for driving light macliinery, and they have been 
largely employed in pumping water. 



HOME MECHANICS FOE AMATEUKS 177 

Quite recently caloric enoiues have been made in the 
form of a toy, as illustrated in the following engrav- 
ing. In the motor here shown, the air contained in 
the expansion cylinder is alternately heated and cooled, 
and no fresh air is introduced. This action is so rapid 




Fig. 195. Small Caloric Engine. 



irS HOME MECHANICS FOR AMATEURS 

iu a small engine that the cranlc shaft can make 600 or 
700 revolutions a minute. By examining the sectional 
views (2, 3 and 4, Fig. 19(3) a good idea of the construc- 
tion and operation of the motor may be obtained. In 

5 




Fig. 196. Sectional Views of Small Caloric Engine. 



brief, the larger and longer of the two cylinders (the 
expansion cylinder) contains a long, hollow piston 
called the ''transfer piston" which fits the cylinder very 
loosely. To this piston is attached a rod extending 
through a close fitting sleeve in the top of the cylinder, 



HOME MECHANICS FOE AMATEUES 179 

the piston rod being provided with a connecting rod 
fitted to the crank at the middle of the shaft. The up- 
per part of the expansion cylinder is furnished with a 
wide flange forming a cap which fits over the sheet iron 
fire box, and to the top of the expansion C3dinder are 
secured the standards in which is journaled the crank 
shaft. 

To the flange is attached the power cylinder, which 
is shorter and smaller in diameter than the expansion 
cylinder. This cylinder is provided with a piston to 
which is pivotally connected the lower end of a connect- 
ing rod, the upper end of Avhich receivef^ a crank pin 
projecting from one of the fly Avheels at right angles to 
the transfer piston crank. A hole bored in the flange 
connects the expansion cylinder and the bottom of the 
power cylinder, as shown in No. 2, Fig. 196, and the 
outer end of the hole is stopped by screw plug which 
can be removed for cleaning the hole, should it become 
stopped by oil or otherwise. 

An alcohol lamp is provided for heating the expan- 
sion cylinder, it being placed in position to heat the 
lower end of the cylinder, as shown in the larger view. 
The top of the lamp is provided Avith a hemispherical 
cavity, at the bottom of Avhich is the aperture for filling. 
The stopper consists of a marble dropped into the 
hemispherical cavity and serving the double purpose of 
stopper and safety valve. 

The expansion and power cylinders contain a certain 
amount of air Avhich is never changed during the op- 
eration of the engine, except by expansion and contrac- 
tion. Heat having been applied to the lower end of 
the expansion cylinder, the engine is started by giving 
the crank sliaft one or two turns in the direction indi- 



180 HOME MECHANICS FOR AMATEURS 

cated bv the arrows on the rims of the fly wheels. The 
air at the top of the expansion cylinder is transferred 
to the lower end of the cylinder by the transfer piston 
as it rises ; at the same time the power piston descends, 
and by this time the air is heated in the lower part of 
the expansion cylinder and begins to expand. The 
power piston is in position to be pushed up by the air 
pressure. As the power piston reaches the upper end 
of its stroke, the transfer piston descends and transfers 
the heated air to the upper end of the expansion cylin- 
der, where it is cooled, thus reducing the pressure and 
allowing the power piston to descend again. This op- 
eration is repeated at every stroke. It is almost impos- 
sible to believe that the air can be heated and cooled 
so rapidly. 

The efficiency of the motor can be increased by sur- 
rounding the upper portion of the expansion cjdinder 
by a Avater jacket provided with a water supply pipe 
at the bottom and a discharge pipe at the top, as 
shown in No. 5, Fig. 196, and keeping a continual flow 
of cool water through the jacket. When the motor is 
used for pumping, the water is forced through the 
jacket. 

This little motor is only a toy, but it very completely 
illustrates the principle of one of the most successful 
hot air engines ever devised. If the reader is mechan- 
ically inclined, he may make a motor on this plan on a 
much larger scale, and use it for driving machinery. 
There can be no doubt about its successful construc- 
tion or operation, if it is made airtight and the bear- 
ings and friction surfaces are made to run free. The 
proportions may be about the same as shown in the 
cut. 



HOME MECHAXICS FOR AMATEURS 181 

The dimensious uf the motor from wliieh the views 
were made are as follows: 

INCHES 

Length of expansion cylinder 4f 

Internal diameter of expansion cylinder liV 

Length of transfer iDiston 2f| 

Diameter of transfer piston IJ 

Length of power cylinder If 

Diameter of power cylinder f} 

Length of cranks tV 

Diameter of fly wheels . 3 

Height of firebox from base 5^ 



AN INEXPENSIVE WATER ^lOTOR 

A simple but very effective w^ater motor can be 
made by any one according to the plan here shown, 
with little trouble or expense. It may be necessary to 
have a few minutes' w^ork done by a tinsmith. The 
maker may do this if he understands soldering. 

In a pine board 7 inches square and 1 inch thick, 
make a round hole 5 inchcfs; in diameter, by the use of 
a scroll saw, or in any other convenient way. To the 
sides of the board fit two thin boards ^ inch thick, 
one on either side. In a small hole in the center of 
each side drive a short piece of brass tube of about J 
inch internal diameter, and to these tubes fit a straight 
steel wire so that it will revolve freely. This wire is 
the shaft of the motor wheel. It should be of sufficient 
length to project an inch beyond its bearings, to receive 
a small pulley. 

To the center of the shaft is soldered a sheet brass 
disk 3 inches in diameter, so that it will run true as 



182 



HOME MECHANICS FOE AMATEUES 



the shaft revolves, and to the disk is soldered a disk of 
brass wire gauze 30 mesh. The edges of the brass wire 
gauze must, as the ladies would say, be sewed over and 
over with a fine copper wire, to prevent it from raveling 
when the wheel revolves rapidly. If the Avorkman is 
an adept he may solder a ring of brass wire, say No. 
18 or No. 20, to the edge of the wire cloth. 




Fig. 197. Motor Driving Sewing Machine. 



The simplest way to secure a nozzle for the wheel is 
to buy a cheap, small oil-can having a long nozzle, with 
an opening in the smaller end of about tV inch. This 
nozzle is inserted into the edge of the Avooden wheel- 
case, as shown, and its smaller end is bent so that it 
forms a small angle with the Avheel, with the point of 
the nozzle as near ^:he wire cloth as possible without 
touching. To cause the wheel thus made to keep a cen- 



HOME MECHANICS FOR AMATEUKS 



183 



tral position in its case, pieces of the small tube before 
named may be slipped on the shaft each side of the 
Avheel. 

A f-inch hole may be made in the casing at the bot- 
tom, and provided Avith a short tube for receiving a rub- 




FiG. 198. Small Water Motor 



ber pipe, to carry off the waste water, and there should 
be a |-inch hole in each side near the top to admit air. 
The casing may be secured to the wooden foot-pieces 
with screws. It is desirable to make the casing im- 
pervious to water. To do this, the various parts may 
be boiled in hot paraffine for ten minutes. If it is 



184 HOME MECHANICS FOK AM.VTEUES 



found difficult to secure paraffine in bulk, a pound of 
paraffine candles Avill furnish enough for this purpose. 
The inflammable nature of paraffine should be kept in 
mind, and a cover should be provided for the vessel in 
which it is melted, so that it may instantly be extin- 
guished by the cover should it become ignited. The 
metal used in the construction of this wheel should be 
of brass, excepting the shaft. The screws with which 
the casing is put together should be brass. The top of 
the oil-can is cut otf to form a part of the coupling for 
receiving the rubber pipe leading from the wash-bowl 
faucet to the motor. 




Fig. 199. Diagram Showing Position of Nozzle. 

To prevent the checking of the wooden parts of the 
motor, the parts should be arranged with the grain 
lying in the same direction. 

With sufficient water pressure, this motor will make 
from 1,500 to 2,000 revolutions per minute. With a 
very flexible cord belt — a leather shoestring, for ex- 
ample — it may be made to drive a light sewing machine, 
fan, or any other machine requiring a small amount 
of poAver 

If more power is required than can be secured by one 
water jet, additional nozzles may be distributed around 
the wheel, or more wheels may be j)laced on the same 



HOME MECHANICS FOR AMATEURS 185 

shaft, but notliin<2: will be gained unless the water 
pressure is maintained. This pressure should be from 
25 to 40 pounds per square inch. 

In a small high-speed motor of the class here de- 
scribed, the full power is realized onl}^ when it is pro- 
vided with a very small pulley connected by a very 
flexible belt with a large pulley on the machine to be 
driven. 

It is obvious a non-corrosive metallic case would be 
better than a wooden one, and the metal one is advised 
when the builder has conveniences for making a casing 
of that kind. 



PART Y. 

METEOROLOGY 

SELF RECORDING INSTRUMENTS 

IF these instruments were constructed so that 
each would produce a permanent record of 
its movements, it would certainly add to 
their usefulness as well as their convenience, 
but it is thought best to confine the construction 
to these simple forms of apparatus, trusting to 
the ingenuity of the reader to apply clock mechanism 
for keeping the records. One eight-day clock could be 
made to do duty for all the instruments. It could be 
geared to a drum so that it would make one revolution 
in one day, or in one week, and each instrument could 
be made to mark on a piece of paper carried by the 
drum. The paper would need to be graduated so that 
the pen carried by each instrument could be readily 
traced. There should be divisions for days and hours. 

The pen by Avhich the record is made is simply a 
small glass tube about ^ inch in internal diameter, 
with the end which bears upon the paper drawn out to 
almost a capillary tube and cut off and made round and 
smooth by heating in a gas or alcohol flame. The ink 
used in this pen is a drop of red ink mixed with an 
equal amount of glycerine. This ink remains in the 
narrower end of the tube and does not evaporate. 

METEOROLOGY 
The subject of meteorology has claimed the atten- 
tion of men to a greater or less extent doubtless since 

[187] 



188 HOME MECHANICS FOE AMATEUES 

the earth began to be iuhabited by hiiniau beiugs. The 
phenomena of the air must have early attracted atten- 
tion and caused the observers to reason from cause to 
effect until there came gradually to be an under- 
standing of earth, air and water — not always correct — 
but in the main pointing to the present development 
of the science, so that after the lapse of many centuries, 
the close student of nature is able to explain various 
phenomena and to predict with more or less certainty 
what will happen, especially in the immediate future. 

To be able to predict the weather Avith a little more 
certainty than the ordinary 'Sveather prophet" can do, 
the student should be in communication with the Gov- 
ernment Weather Bureau, so as to avail himself of 
the observations of others; but even without such 
facilities as these many interesting observations may 
be made with the simple apparatus hereinafter de- 
scribed, and notes ma^^ be kept for future reference. 

This kind of observation is instructive in several 
ways. The very act of making frequent observations 
induces a methodical habit which Avill be valuable 
through life, and the observations are interesting and 
instructive in themselves. Besides all this, the record 
formed is likely to be valuable for both present and 
future use. 

WHAT MAY BE LEARNED BY THE USE OF THE 
METEOROLOGICAL INSTRUMENTS 

When we find the weather vane iDointing toward the 
west we look for clear weather, and as a rule we are 
not disappointed ; but when the vane indicates that the 
wind is blowing from the east, a storm is expected. 



HOME MECHANICS FOR AMATEURS 189 

When it blows from the north, cool weather may be 
looked for, and when it blows from the south, it hardly 
ever fails to bring sultry days in summer and thaws 
in winter. 

When the wind blows strong from any direction, 
curiosity is aroused as to the pressure it is exerting. 
This may be ascertained by observing the wind pres- 
sure gauge ; 1^ pounds pressure shows that the wind is 
blowing fifteen miles per hour ; 4^ pounds pressure per 
square foot represents a velocity of thirty miles per 
hour ; 18 pounds pressure indicates a velocity of sixty 
miles an hour, and 50 pounds pressure is registered 
during a tornado one hundred miles an hour. In 
calculating the pressure as indicated by this gauge 
it must be remembered that the board which offers 
resistance to the wind has only a half square foot 
area. 

The velocity of the wind is shown by the anemometer. 
Wind is hardly noticeable when it blows a mile an 
hour. When it blows live miles an hour it is a pleas- 
ant breeze; when it ])lows ten miles an hour it is a 
brisk breeze; when it blows at a twenty-mile rate it is 
a stiff breeze; at thirty miles it is a high wind, and at 
forty miles it is a very high wind. At eighty miles it 
is a hurricane, and at a hundred miles per hour it is 
a tornado. 

THE AVEATHER VANE 

The weather vane hardly needs explanation to make 
it understood. In the top of a stout pole is inserted 
a i-inch rod which is bluntly pointed at its upper 
end. On this is placed a vane consisting of a wedge- 
shaped piece of hard wood with a hole through it, a 



190 HOME MECHAXICS FOE AMATEURS 

piece of hoop iron beiug fastened over the hole and 
resting on the upper end of the blnnt-pointed rod. 

To opposite sides of tlie wedge are secured pieces 
of ^-inch board 4 inches' wide and 20 inches long. 
These pieces are let into the faces of the Avedge so 




Fig. 200. Weather Vane. 

as to form continuous surfaces. The boards diverge 
so that their free ends are about 2| inches apart. 
This construction insures steadiness. 

The tliin end of the wedge has an arrow-headed arm 
])rojecting from it to indicate the direction of the 
wind. In the sides of the pole, near the upper end. 
are inserted four :[-inch rods arranged at 90 degrees 
with each other, and in slots sawed in the ends of the 
rods are riveted letters which indicate the points of 
compass, N., S., E. and W. These, in connection with 
the arrow-headed arm, enable the observer to tell which 
Avay the wind blows. 

WIND PRESSURE GAUGE 

The construction of a Avind pressure gauge is as 
simpk^ as that of the ordinary Avindmill, Avhich every 
boy knows hoAV to make. A Avind A^ane 6 inches Avide 
and 24 inches long is made of a J-incli board, on tlie 



HOME MECHANICS FOK AMATEUES 101 

edge of wliicli is secured p. piece of band iron wliicli pro- 
jects over the end of the l)oard about 1.^ inches. In the 
end of the board are inserted two screw-eves for receiv- 
ing tlie rod upon which the A'ane swings. The upper 
end of the rod is pointed bluntly, so that the piece of 
band iron which rests upon it allows the vane to swing 
freely in any direction. 

The middle portion of the board is cut away from the 
upper edge to admit of placing a spring scale for the 
measurement of the wind pressure. In the upper 
edge of the board at opposite ends of the scale-notch 
are inserted wire screw-eyes to receive the horizontal 
Avooden rod which carries the wind-pressure board, 8 
by 9 inches long and } inch thick. 

The board is stiffened by a cleat on the back, which 
is bored to receive the rod. A screw hook is inserted 
in the rod, and another is inserted in the upper edge 



r: 




FiG. 201. Wind Pressure Gauge. 



of the vane for receiving, respectively, the eye and 
hook of the scale. The spring scale is adjusted so as 
to hold the thin board a little more than the length 
of the slot in the spring-scale away from the pivot 
of the vane when the wind is light or nil. When the 
wind blows the vane keeps the instrument headed 



192 HOME MECHANICS FOR AMATEURS 

toward the wind, and the scale indicates the pressure 
on a half square foot, so that the reading must be 
multiplied by 2 to secure a correct pressure. 

The rod should be inserted in a rigid post and must 
be exactly vertical. 

The amount of rain falling in a given time can 
be ascertained approximately by placing any kind of 
vessel having parallel sides out of doors in an open 
place where it may receive all the rain, and then 
measuring the depth of the water after the rain by 
means of a small stick plunged into it; the depth 
being registered by the wet portion of the stick. This 
method, however, is crude and open to objections; 
some of the water will spatter over, some Avill be lost 
by evaporation, and some will be displaced by the 
stick. 

If the observer is really in earnest he should make, 
or have made, a copper vessel like the one shown in 
the illustration. It is 4 inches in diameter and 6 
inches high, with the bottom set in 1 inch so as to 
receive the copper tube, which is bent twice at right 
angles, with its inner end inserted in the recessed bot- 
tom and its outer end extended up outside the vessel, 
and even with the bottom to receive a f-inch glass 
tube, which is cemented therein with a cement consist- 
ing of white lead paint and litharge formed into a soft 
putty. 

The glass tube is 7 inches long, and furnishes a 
ready means of ascertaining the depth of water in 
the vessel when viewed in connection with the scale 
of inches attached to the vessel. 

In the top of the vessel is inserted a funnel 3^ inches 
long, with a cylindrical portion at the top 2 inches 



HOME MECHANICS FOR AMATEUES 193 

deep. The upper and lower edges of the main vessel 
are wired to give them rigidity, but the cylindrical 
top of the funnel is not wired. 

A rubber band may be stretched around the funnel 
at the junction of the cylindrical and conical portions 
to prevent waste by evaporation at this point. To 




Fig. 202. Rain Gauge. 

insure accuracy the copper pipe Avhich holds the glass 
tube should be filled with water before the observa- 
tion begins. 

When the gauge is used in a windy place it should 
be clamped to some fixed object by three screws en- 
gaging the wire rim at the bottom of the vessel. 



194 HOME MECHANICS FOE AMATEURS 

A METALLIC THERMOMETER. 

A mercurial thermometer calls for manipulations 
which are not within the scope of the amateur, but 
require the skill and experience of the regular manu- 
facturer. A metallic thermometer, however, is very 
easily made, and serves the purpose fully as well as a 
mercurial thermometer. It can be made as sensitive 
to the variations of temperature as may be desired. 

It is made by placing together a strip of steel and 
one of brass 6 inches long, J inch wide and A inch 
thick. The ends of the strips are tinned for about f 
of an inch at each end of their adjacent faces, and 
then put together and heated first at one end and then 
at the other, so as to solder them together at the 
ends. 

The brass strip is made about i inch longer than 
the steel strip, and is bent over and perforated to re- 
ceive a silk thread as will be presently explained. Com- 
monly, Avhen strips of steel and brass are used in a 
compound bar, they are riveted at short intervals, to 
keep them from buckling. In the present case the 
compound bar is provided with a winding of soft wire 
(No. 30) which keeps the strips close together. To in- 
sure permanency the bars are drilled and riveted with 
a single rivet at each end. 

The compound bar thus made is inserted in a round 
hole in the middle of a hard wood block 2J inches 
long, and held there by an ordinary wood screw in- 
serted in the end of the block and clamping the end of 
the bar. The wooden block is secured to a base piece, 
4 inches square and | inch thick, having attached to 
it a back board J inch thick, 4 inches wide, and about 



HOME MECHANICS FOR AMATEURS 195 

10 inches high. A wire nail abont tV in^h in diameter 
and 1^ inches long is driven through the back with its 
pointed end projecting about 1^ inches. The nail is 
about f inch from the upper free end of the compound 
bar. A paper roll is formed upon another nail or a 
piece of wire a trifle larger than the one used in the 
construction of the thermometer. The strip of writ- 
ing paper used for this roller should be 1 inch wide 
and about 8 inches long. Enough of the paper is wound 
to make the roller ^ inch in diameter. The paper, 
except the first layer, is pasted as it is rolled, so that 
it forms a solid paper roll when it is dry. 

This roll, when dry, is transferred to the nail pro- 
jecting from the back piece, and a pointer, or index, 
about 2^ inches long is cut from thick writing paper 
and glued to the end of the roll. Then a silk thread 
is tied in the eye in the free end of the compound bar, 
and passed over the roller on the nail, and wound 
three times around the roll, and it has attached to it a 
small weight. In the present case this weight consists 
of a lead bullet split half open with a knife, and 
closed down upon the thread by pliers or by hammer- 
ing. With every change in temperature the compound 
bar swings, so as to cause a movement of the index by 
the pulling or releasing of the thread and the raising 
or lowering of the weight. 

The index should be placed in a vertical position 
Avhen the temperature is about 70° ; then the winding 
of the silk should be separated a little, and a small 
drop of mucilage should be placed on the middle con- 
volution of the thread at the top of the roller, so as 
to cement it to the roller and prevent any change of 
adjustment. 



196 



HOME MECHAXICS FOK AMATEURS 



A semicircular piece of bristol board, about 6 inches 
in diameter, is temporarilv supported behind the index 
by a block glued to the back piece. The bristol board 
is to form the thermometer scale and is fastened to 






Fig. 203. A Metallic Thermometer. 

the block by tacks or otherwise, so that it can be re- 
moved and accurately replaced. A pencil mark is now 
made on the scale at the point of the index which indi- 
cates the temperature as shown by a mercurial ther- 
mometer at the time. If it is 70°, the mark on the new 



HOME MECHANICS FOE AMATEITES 107 

scale represents (liis tempeniture, and wlieuever the 
index points to this mark the observer knows the 
thermometer is 70°. 

Now the thermometer is placed in a refrigerator 
along with a mercurial thermometer. They are left in 
the refrigerator for an hour, and then a pencil mark 
is made at the point of the index. This will, perhaps, 
be 40°. The space between these two marks is divided 
into thirty even spaces, representing as many degrees, 
or it may be divided into fifteen spaces, each of which 
will represent 2°. This graduated space serves as a 
guide for constructing the balance of the scale. If 
2° spaces are used, twenty such spaces laid off on the 
left-hand side of the scale will extend the scale to 
zero. Twenty more such spaces will extend the scale 
to 40° below zero, which is lower than any temperature 
experienced in this climate. The space between 40° 
and 70° is already graduated, and the space above the 
70° mark is graduated as described for the lower end 
of the scale. As each line represents 2°, 10° would 
])e represented by five lines, so that the fifth line could 
be extended beyond the other lines for the sake of con- 
venience in reading. Figures from 0° are placed op- 
posite the long lines so as to read 10°, 20°, 30°, 
40°, and so on, as in an ordinary thermometer scale. 

The amateur can refine this thermometer as much as 
he pleases. He may, if he desires, place the entire de- 
vice in a case and cover the dial with a glass, provided 
he furnishes several apertures to enable the air to cir- 
culate and thus keep the temperature the same as that 
of the external air. The free end of the compound bar 
may have a spring riveted to it, as shown in the de- 
tached view, and an adjusting screw may be inserted in 



198 HOME MECHANICS FOR AMATEURS 

the compoiiud bar so as to bear against tbe spring. 
AVith this constrnction, the silk thread may be tied in 
a hole in the free end of the spring, and the desired 
adjustment may be made by turning the screw one way 
or the other. 

By making the compound bar longer, or diminishing 
the diameter of the c^dinder around which the thread 
extends, or both, the sensitiveness of the instrument 
may be greatly increased. 

SIMPLE HYGROSCOPE 

No instrument is required to indicate a superabun- 
dance of humidity in the air. Everyone knows the dis- 
comforts of a moist, hot day in the summer without 
requiring a hygroscope. Still, to one scientifically 
inclined it is some satisfaction to know the hygrometric 
state of the air, and to compare one day with another 
of the same year or previous years. 

A very simple hygroscope which is accurate enough 
for all practical purposes is illustrated by the engrav- 
ing. Its construction Avas suggested by a panel made 
of two pieces of wood glued crosswise to keep it straight 
— the very best arrangement of the grain for causing 
it to assume a concavo-convex form under all condi- 
tions of the atmosphere except that in which it was 
glued together. It has a baseboard 4 inches square 
and I inch thick, with a back piece 4 inches wide and 
13 inches high and ^ inch thick, attached to one edge. 
Near the right-hand edge of the base is secured a block 
to which is attached a hygroscopic strip made up of 
a longitudinal piece of any elastic wood (such as white- 
wood) 12 inches long, 1 inch wide and tV inch thick. 



HOME MECHANICS FOE AMATEUES 199 

and a transverse piece of white wood of the same thick- 
ness 1 inch long and 12 inches wide, carefully glued to 
it, so that the grain of one strip is at right angles to 
that of the other. These strips of wood should be well 




Fig. 204. Hygroscope. 



Fig. 205. Hygroscope Strip. 



seasoned. This compound strip is secured to the small 
block on the base of the instrument, and a piece of plain 
cardboard is attached by two tacks to the wooden back 
at the center of the board, 



leaving the ends of the card 



free. The concave side of the strip should be arranged 



200 HOME MECHANICS FOR AMATEURS 

to face the left-hand side of the instrument, and a short 
piece of small wire, say No. 24, or a headless pin should 
be inserted point outward in the free end of the strip 
to serve as an index. 

The scale is constructed by first placing the instru- 
ment under a bell glass with several pieces of wet 
blotting paper near but not touching the strip. The 
long, narrow strip does not change its length, but is 
bent one way or the other by the swelling or shrink- 
ing of the piece which is glued crosswise. The hygro- 
scopic strip will straighten out or even curve in the 
opposite direction when submitted to the influence of 
moisture, and after the lapse of six or eight hours 
the glass is removed and a pencil mark is made on the 
card at the point of the index, which will rep- 
resent 100 degrees, or the point of saturation. The 
instrument is allowed to assume the normal position 
by drying it in the open air, after which it is again 
placed under the bell glass with a dish of calcium chlo- 
ride and allowed to remain five or six hours. The cal- 
cium chloride removes the moisture and causes the 
cross-grained side to shrink and thus curve the strip 
considerabl3\ It now indicates the maximum dryness 
of the air, and a mark is made at the point of the index, 
indicating zero. The spaces between zero and satura- 
tion should now be divided into ten equal spaces, and 
each space may be subdivided into ten spaces, each 
representing one degree. 

These lines should be neatly made with a drawing 
pen. Every tenth graduation should be extended a 
little and numbered; the entire scale being numbered 
from to 100, i. c, 0, 10, 20, 30, etc. 

This instrument is not intended to accurately show 



IIOMl^] I\rECILVNICS YOU AMATEUKS 201 

the exact amount of inoistiire, as is the case with the 
more elaborate hygrometers, but to afford a simple 
means of showing the ever-varjing state of the air. 



MERCURIAL BAROMETER 

The variations of atmospheric pressure are shown 
by the barometer. The pressure of the air in round 
numbers is 15 pounds per square inch ; that is, a col- 
umn of air 1 inch square, the height of the atmosphere 
(which is not positively known), weighs 15 pounds, 
and will balance a column of water 1 inch square and 
31 feet high, or a column of mercury 1 square inch in 
area and 30 inches high. 

A mercurial barometer is here shown on account of 
facility of construction and the accuracy of its opera- 
tion. To make the simplest form of mercurial barom- 
eter, a strong glass tube a little more than 33 inches 
long and about tV inch internal diameter is required. 
It must be sealed at one end, and left open and con- 
tracted to I inch at the other. This work is readily 
done by a glass blower. The open end is fused to 
remove the sharp edges. A small glass bottle is pro- 
vided, the body of which is about 1 inch internal diam- 
eter and 1^ inches high. The neck is short and a 
little larger internally than the outside of the tube. 
A board | inch thick, 3 inches wide and 39 inches long 
has a shallow half-round groove to receive the glass 
tube, and two brass straps extend over the tube and 
are clamped to the board by means of screws. Near 
the bottom of the board a hole is cut for the glass 
bottle or cistern, as it is called ; a small shelf is secured 
by screws to the back board, even with the lower 



202 



HOME MECHANICS FOE AMATEUES 



side of the hole in the board. A small hole is made 
in the back board near the top to receive the nail or 
screw upon which the instrument hangs. 




Fig. 206. Scale and Indicator. Pig. 207. Mercurial Barometer. 



Of course all the parts will be tried in place before 
attempting to fill the tube with mercury. 

The tube must be perfectly clean, and only re-dis- 
tilled mercury should be used. In the bottom of the 



JIOMF. :\[ECHAXICS FOE xViyiATEITES 203 

glass bottle is placed a layer of pure beeswax tV iii<*b 
thick. The wax is made smooth and level by melting 
it by gently heating the glass bottle over an alcohol or 
Runsen gas flame. When the wax is cold the filling 
of the tube with mercury may be proceeded with. The 
tube and the mercury are first warmed by passing 
them over an alcohol or gas fiame; then mercury is 
poured into the tube through a small paper funnel. 
The tube should be filled to within ^ inch of the 
end with mercury. Then the clean, dry forefinger is 
held over the open end of the tube and the tube is 
placed in a horizontal position and tilted one way and 
then the other, to alloAv the bubble of air to gather 
up as much as possible of the air contained in the tube. 
The tube is then placed open end up and entirely filled 
with mercury. It is then inverted while it is kept 
closed b}^ the finger. The end of the tube is placed be- 
low a body of mercury in a suitable vessel and a little 
of the mercury is let out so as to produce a partial 
vacuum at the top. Then the tube is closed and again 
turned into a horizontal position and tilted in one way 
and then the other, and at the same time turned or 
rolled over so as to cause the bubble to gather up any 
air that may remain. The tube is again inverted and 
filled, until it is entirely full of mercury. The finger 
is again applied, and a vacuum is produced hj allow- 
ing a small amount of mercury to escape, when the 
tube is vertical as before. It is closed and tilted, allow- 
ing the bubble to again gather air. This operation is 
repeated two or three times. The tube is finally in- 
verted and filled with mercury, so as to present a 
convex surface above the oj)en end of the tube. The 
glass bottle containing the wax is placed over the 



204 HOME MECTTAXTCS FOE AI\rATErES 

open end of the tube and pressed down, eausing the 
wax to make a good eontact with the end of the tube. 

The bottle is held firmly in place by the finger, and 
the bottle and the tube may now be inverted together, 
and after putting a little mercury in the bottle, the 
latter may be placed on the shelf prepared for it, and 
the tube may be raised a little, so as to clear its open 
end from the Avax, and the tube is fastened in place 
by clamping it with the brass strips and screws. More 
mercury is added to that in the bottle so as to make 
the depth about f inch above the lower end of the 
tube. A quantity of clean cotton wool is placed in the 
mouth of the bottle around the tube to exclude dust, 
at the same time to admit air freely. The barometer 
is now finished with the exception of the scale. 

A scale of inches f inch Avide and 4 inches long is 
laid out in the center of a card 2^ inches wide and 
6^ inches long. Each inch is divided into tenths, and 
the divisional lines for the inches and half inches are 
extended beyond the J inch limit. The beginning of 
tlie scale is numbered 27. The upper end of the first 
inch is numbered 28, the second inch is numbered 29, 
the third inch 30, and the fourth inch 31. The scale 
is placed behind the tube and the division line corre- 
sponding with the line at the top of the mercury in a 
standard barometer is placed in the same position rel- 
ative to the mercury, and fastened by small tacks. 

To enable the observer to mark the height of the col- 
umn of mercury, so that he may compare the present 
observation with the previous one, an indicator is pro- 
vided, which consists of a rod supported by posts at- 
tached to the board, and a short section of spiral 
spring placed on the rod, with the upper extremity 



HOME MECHAXICS FOK AMATEUES 205 

straightened and extending over the barometer tnbe. 
This end of the wire is flattened by hammering to make 
a more delicate index. 

In a general way the changes of the barometer are 
given, bnt tliey mnst be taken with some allowance. 
High winds and storms usually follow the sudden drop 
of the mercury. The rising of the mercury generally 
indicates fair Aveather; the drop of the mercury indi- 
cates bad weather. The fall of the mercury in sultry 
weather is followed by thunder ; the rise of the mercury 
in winter indicates frost. In frosty weather the fall 
of the mercury precedes a thaw, and the rise is followed 
by snow. Sudden changes in the barometer indicate 
similar changes in the weather. Continued foul 
weather may be expected if the mercury falls slowly; 
on the contrary if it rises slowly continued fair weather 
may be looked for. Changeable weather is indicated by 
an unsettled barometer. 

It is perhaps unnecessary to caution the maker of 
the barometer to conduct the various operations of 
filling and adjusting above a large platter or piece of 
smooth paper, with the edges turned up to avoid un- 
necessary waste of mercury. 



PART VI. 

TELESCOPES AND MICROSCOPES 

HOW TO MAKE A TELESCOPE 



N 



O ONE can look into the starry depths at 
night without a feeling of wonder and awe, 
nor is this feeling lessened when the mind 
grapples the question of space and con- 
templates the awful abysm that separates us from 
even the nearest star, to say nothing of the points 
of light faintly visible to the naked eye, nor of the 
telescopic stars removed to such distances as to be- 
wilder the mind and baffle the imagination in the 
attempt to realize their remoteness. 

Who does not desire to become more familiar with 
these distant bodies and to possess all the knowledge 
that can be obtained by observation? Much can be 
done by the unaided eyes, and a great deal more can 
be accomplished by means of a telescope of very mod- 
erate proportions and power. x4n ordinary opera glass 
is not to be despised, but of course an instrument with 
a larger objective and a longer focus is much more 
efficient and desirable. 

Our engraving represents the telescope, its standard, 
and the A^arious parts, in section and in detail. The ob- 
ject glass. A, shown in the engraving, is a meniscus 
lens 2| inches in diameter and 36 to 38 inches focus. It 
is mounted in a wooden cell, B, having an internal 
flange or fillet about tV inch wide, forming a true sup- 
port for the lens and bearing against the end of the 
paper tube, D, which forms the body of the telescope. 

[ 207 ] 



208 



HOME MECHANICS FOE AMATEUKS 



The lens is retained in its ceH bj a flat strip, E, of brass 
which is sprung into the cell and is pushed down 
against the lens. The cell is fastened to the tube by 




Fig. 208. A Simple Telescope. 

common wood screws, which pass through the collar 
into the paper forming the tube. It is perhaps needless 
to say that the cell should be made of some thorou«hlv 



HCBIK ]\rp]CHANlCS FOR AMATEUKS 209 

seasoned hard wood, which is not liable to atmospheric 
influences. Hard maple answers a good purpose, but 
mahogany is to be preferred. 

To protect the objective Avhen not in use a cap, F, of 
tin or pasteboard neath^ covered with morocco or 
velvet is fitted to the cell. 

The paper tube of which the telescope body is formed 
is such as is commonly used for rolling engravings for 
mailing. It is 3 inches external diameter and 32 inches 
long (about 4 inches shorter than the focus of the 
objective). The exterior of the tube is covered with 
Java canvas attached by means of bookbinder's paste 
(flour paste with glue added), and varnished when dry 
with tw^o or three thin coats of shellac varnish. This 
gives the tube an elegant and durable finish. 

The focusing tube, G, which is of brass, I7I inches 
internal diameter, and 12 inches long; is guided by a 
turned wooden piece, H, fitted to the end of the paste- 
board tube, D, and held hj three or four ordinary 
round-headed wood screws. 

The piece, H, has a shoulder, a, against which the 
end of the pasteboard tube abuts, and only about three- 
quarters of an inch of the piece, H, actually fits the 
tube, the portion from 5 to c being tapered as indicated 
in the engraving, and near the extreme inner end, 
about 3^ inches from the shoulder, there are three 
screws, d, used in collimating the focusing tube, G. 

The bore of the piece, H, is somewhat larger than 
the focusing tube, G, and is provided with a cloth lin- 
ing, e, at each end to insure the smooth working of 
the tube. 

A short distance from the shoulder, a^ a mortise 
about three-quarters of an inch square is made tlirough 



210 HOME MECHANICS FOR AMATEURS 

the side of the tube, D, and the piece, H, and a trans- 
verse slot, fj is formed to receive the wooden spindle, I, 
which is enlarged in the middle to receive the rubber 
thimble, J, and has on one end a milled head by which 
it may be turned. The spindle, I, is held in place by 
concave pieces, g^ which in turn are retained by the 
curved plate, Jc, attached to the tube, D, by screws. 
The rubber thimble, J, must be of sufficient diameter to 
reach to and press upon the focusing tube, and the 
latter has a series of transverse grooves filed in it. 
This will insure sufiflcient friction to move the tube, 
G, in and out when the spindle, I, is turned. This sim- 
ple device replaces the usual focusing mechanism, and 
is to be preferred to a rack and pinion, unless the latter 
be perfectly made, and it is certainly superior on the 
score of cheapness. 

The cell, B, piece, H, and spindle, I, should be 
blacked and polished on the outside, and the cell should 
be left dead black on the inside. The interior of the 
tubes should also be dead black. This surface may be 
secured by adding lampblack to a little very thin shel- 
lac varnish, and applying it to the inside of the tube by 
means of a swab. The focal lengths of the lenses of 
the astronomical eyepiece should be to each other as 
three to one; the field lens, which is nearest the object 
glass, having the greatest diameter and the longest 
focus, and the convex side of each lens should be turned 
toward the object glass. Their distance apart should 
be one-half the sum of their focal lengths. These lenses 
are mounted in a wooden cell, L, whose exterior is 
fitted to the focusing tube, G, and grooved circumfer- 
entially to receive a strip of cloth, which is glued in, 
and insures a good fit. The cell is bored in ditferent 



HOME MECHANICS FOE AMATEUES 211 

diameters to receive the field lens, h^ the diaphragm, i, 
and the eve lens, y, all of which are held in place against 
the shoulders formed in the cell by circular springs of 
brass, which are sprung in as in the case of the object 
glass. The e^^e aperture should be about -} inch, and 
the aperture of the diaphragm should be about the 
same. 

It is well enough to make the diaphragm adjustable, 
so that it may be moved back and forth to secure the 
best position. It will be found, however^ that, if placed 
just beyond the focus of the eye lens, it Avill give the 
best results. 

A circular recess, k, is formed in the face of the eye- 
piece to receive a sun glass, which is retained in place 
when in use, by a short curved spring, /. The sun glass 
is simply a disk of very dark glass. It must, in fact, 
be nearly opaque; some of the glass, known as black 
glass, answers the purpose very well. 

If but one astronomical eyepiece is made, probably 
the most satisfactory combination would be: Field 
lens, 1^ inches focal length ; eye lens, -^ inch ; distance 
apart, 1 inch. It is advisable, however, to have three 
eyepieces for different purposes — one of higher power 
and one of lower power than the one described. 

In this connection, I will describe a terrestrial eye- 
piece, referring to the sectional view. Fig. 209, al- 
though it is of little use to adapt such an eyepiece to 
this instrument unless it is first provided with an 
achromatic objective. It is then a powerful telescope, 
which will enable one to see well for many miles. The 
method of mounting the lenses described in connection 
with the astronomical eyepieces will be followed here, 
therefore little more than the diameter and focus of 



212 



HOME MECHANICS FOU AMATEURS 



the lenses and their distance apart need be given. 
There are four plano-convex lenses, A', B', C, I)', 
mounted in two pairs in Avooden cells, E', F', fitted to 
the tube, G', which in turn is fitted to the focusing 
tube, G. The cell, E', has a ^-inch aperture for the eye 
and a bead which projects beyond the tube, G'. 
The lens. A', is about tV inch in diameter and 1 inch 




Fig. 209. Details of Telescope and ferrestrial Eyepiece. 



focus. The lens, B', is f inch diameter and 1^ inch 
focus. The lens, C, is tV inch diameter, 1| inch focus. 
The lens, D', is f inch diameter and 1} inch focus. The 
plane face of A' is If inches from the phuie face of 
B', and a stop, IT, having a tV inch aperture, is placed 



HOME MECHAXTOS FOE AMATEURS 



213 



1^ inches fi'oin the face of the lens, A'. I/'rom the plane 
face of the lens, IV, to the jilane side of the lens, C, 
it is 3| inches. The distance between the plane side of 
the lens, C, and the plane face of the lens, I)', is 1 J 
inches. At a distance of iV iueh from the face of the 
h^ns, C'^ there is a diaphragm, T, having a ^-inch aper- 
ture. It will be observed that the convex sides of the 
lenses, C D, are turned toward each other. 




Fig. 210. Details of Telescope. 



At the extreme inner end of the tube, G', there is a 
diaphragm, K', of if aperture, which is held in place 
by two circular springs. The interior surfaces must 
be well blacked to prevent reflection. 



214 HOME MECHANICS FOR AMATEUES 

I have given cheap yet efficient methods of holding 
the lenses. If desired the reader may, of course, make 
the mountings of brass, and fit the instrument up ac- 
cording to his taste and ability. 

The arrangement of the various parts is clearly 
shown in the sectional view, No. 3, Fig. 209, and the 
focusing device is shown in No. 3, Fig. 210. 

In regard to the matter of collimation I have found 
that by cutting off the ends of the paper tube truly in 
a lathe, the cell, B, and the piece, H, Avill be meas- 
urably true. To determine whether the focusing tube, 
G, and cell, B, are axially in line, a truly cut cardboard 
disk with a pin hole exactly in the center, may be 
placed in the cell, B. A similar disk may also be placed 
in each end of the focusing tube, G. 

Now, by adjusting the piece, H, by means of the 
three screws, (/, the three pin holes in the disks may be 
readily brought upon the same axial line; then, if the 
lenses have been carefully centered by the manufac- 
turer, the telescope will be found sufficiently well 
collimated. If, however, it is desired to ascertain 
whether the lens is truly centered, it may be turned in 
its cell, while the telescope is in a fixed position, and 
directed at some immovable object. If the image moves 
as the lens is turned, it shows that the work has been 
carelessly done. 

If there are doubts as to whether the axis of the 
objective coincides with the axis of the tube, the tube 
may be supported in V-shaped supports adapted to the 
truly turned ends. Then by placing a candle at some 
distance from the face of the lens, and turning the 
tube in its V supports, at the same time viewing the 
reflection of the candle in the lens, it will at once be 



1 



HOME MECHAXICS FOR AMATEUES 215 

known by the movement of the reflection that the cell 
requires adjustment to render the axis of the objective 
and that of the tube coincident. 

With a telescope of this description a large number 
of celestial objects may be examined with great satis- 
faction. The Moon furnishes an unending source of de- 
light, showing, as it does, a face that is ever changing 
throughout the lunar month. Jupiter may be coming 
into good position and affords an interesting study 
of which one does not soon tire. The telescope de- 
scribed will show the satellites in their varying posi- 
tions from night to night. It will show the dark band 
across the face of the planet, and will afford a realizing 
sense of the magnitude of this great body. 

Saturn may be in a good position for observation, 
and his ring may be clearly seen. The meniscus len^ 
will show a little color, and its definition Avill be quite 
defective when directed to such bright objects as the 
Moon, Jupiter, Saturn, Mars, or Venus with the 
full aperture, therefore the aperture should be re- 
duced by a diaphragm of cardboard. A little experi- 
ment will determine the best sized aperture. For nebu- 
lae, star groups, and double stars, the full aperture 
should be used. The great nebula of Orion is an inter- 
esting object ; many of the star groups are very pleas- 
ing, the Pleiades for instance. The sun also, when the 
spots are visible, is a satisfactory object for this instru- 
ment. Of course, the sun glass will be applied before 
the observer attempts to view the Sun, otherwise the 
eye may be injured or destroyed. It may be that some 
reader of this article may have a double or plano-con- 
vex lens of long focus, which he might desire to press 
into the service. Either of these may be used, but the 



216 HOME MECHAXICS FOE AMATEUES 

meniscus is better. If a good job is made of the mount- 
ings it will not be long before the meniscus, or the 
piano or double convex lens will be supplanted by a 
good achromatic objective, which will increase the 
efificiency of the instrument many fold. Such a lens 
is not very expensive. It may be procured from almost 
any optician. 

As to the telescope stand little need be said, as its 
construction is so clearly shown in the engraving. I 
will say, however, in the beginning, that there is no 
danger of getting it too solid. If it is very clumsy it is 
no matter. If it is slender it will be like a ''reed shaken 
by the wind," only ''more so,'' as every tremor has the 
benefit of the magnifying powers of the telescope and is 
amplified to a wonderful extent. 

There are undoubtedly better stands than the one 
represented, but it is easily constructed and answers an 
excellent purpose. From the ground to the toj) of 
the hexagonal hub, M, it is four feet. Three of the al- 
ternate sides of the hub are wider than the intermediate 
ones, to receive the wrought iron hinges by which the 
legs are attached. To attach the hinges, the pin is first 
driven out; one-half of the hinge is then attached to 
the leg, and the other half to the hub, M, when the pin 
is replaced. 

No. 1, Fig. 209, is a top view of the hub and the upper 
portion of the legs. No. 4, Fig. 210, is a vertical section 
on the line, g, fj, in Fig. 209. A H-inch hole is bored 
through the hub to receive the standard, N, which sup- 
ports the telescope and is clamped at any desired 
height by the thumb screw, ni. To prevent marring the 
standard a piece of sole leather is interposed between 
the screw and standard. An arm, ??, is hinged to each 



HOME .MECHxVXlCS FOE AMATEUliS 217 

of the legs and folds down upon the standard, so as 
to spring the legs outwardly, and thus render the stand 
very rigid. The lower ends of the legs terminate in 
spikes, and a strap is attached to one of the legs to 
fasten them all together when the instrument is not 

in use. 

The upper end of the standard, N, is reduced in 
size, and made slightly conical for receiving a socket, 
O, to the upper end of which is jointed an arm attached 
to the V-shaped trough, P, in which the telescope is 
secured by straps. The form of the joint is shown in 
Fig. 210, which is a vertical transverse section taken 
through the socket, O, trough, P, and body of the tele- 
scope. A strong bolt, o, forms the pivot of the joint 
between the socket, O, and trough, P, and is provided 
with a wing nut by which it may be tightened. The 
surfaces of the joint as well as the upper end of the 
standard should be coated with black lead to insure 
smooth working. A post set firmly in the ground, 
while it cannot be moved from place to place, has the 
advantage of being rigid, and forms one of the best of 
cheap stands. A fixture screwed in the window casing 
of a south window, and another attached to a north 
window, afford solid supports for the instrument, and 
have the additional advantage of permitting the ob- 
server to remain under cover. 



218 HOME MECHANICS FOE AMATEUES 



THE MICROSCOPE 

The man ^yho has passed boyhood without knowing 
something of wliat is revealed by the microscope, has 
missed one of the pleasures of life, and has failed to 
look into one of the most interesting and profitable 
studies open to the seeker after knowledge. 

Probably the best form of simple microscope for the 
beginner is a Doublet, of which three forms are shown 
in the engraving. If this cannot be had, a cloth tester, 
or a jeweler's eyeglass, will show much which the eye 
cannot see distinctly. The doublet consists of two 
plano-convex lenses mounted in a short tube with their 
convex surfaces facing each other, and separated by a 
distance equal to one-half the sum of their focal 
lengths. 

The habit of using the lens creates the habit of ob- 
servation, and this rapidly increases one's fund of 
general information. 

The doublet is convenient and inexpensive. Its 
power, however, is fixed. If a different power is re- 
quired another doublet will be needed. Probably 
three-fourths inch is the most useful focus. 

Better for real work is the microscope shown in 
Fig. 212. It has a glass plate on which to place 
the object to be examined, and is provided with a 
mirror to reflect light from below up through trans- 
parent or translucent objects. The arm which carries 
the lens swings so as to bring the lens over any part of 
the plate and slips readily up or down to bring any part 
of the object into focus. The lenses are doublets. They 
may be had of H inch, 1 in., ^ in., and ^ in. focus. 
Probably the | inch and ^ inch will prove the most 



HOME MECHANICS FOR AMxVTEUES 



219 



serviceable^ The wooden base is beveled at either end 
to form rests for the hands in manipulating the objects 
and lens. 

In a slide under the base is placed a metal plate 
enameled black on one side and Avhite on the other. 
This is to be placed on the glass stage when opaque 
objects are under examination. 

This instrument will not take the place of a com- 
pound microscope, but it answers very well when only 




Fig. 211. Dissecting Microscope. 

a low power is needed. If the user develops a taste 
for microscopy and purchases a regular microscope, the 
dissecting microscope will still be of value to him in 
the preparation and preliminary examination of objects 
to be examined ])y the higher power of the compound 
microscope, so that the purchase of a dissecting micro- 
scope is only introductory to the study of microscopy. 
Interesting objects for the dissecting microscope are 
plant hairs on the back of the leaf of the Deutzia 



220 HOME MKCHAXICS FOE AMATEHES 

j[>Ta('ilis, or S])ir;pa, and luany otlier loav(»s \\ith sur- 
faces roii<ih to tlie toucli. ^Many of the mints and fig- 
worts have hairs wonderfully branched. Pollen, 
seeds, wings and antennae of butterflies, mosses, spore- 
cases of ferns, insects, parasites, hairs, feathers, min- 
erals, crystals, — all are interesting and instructive. 
The formation of crystals on the glass stage is very in- 
teresting. 

Drop a small quantity of a solution of alum, com- 
mon salt, sulphate of copper, or other chemical salt, 
sal ammoniac for example, upon the glass stage and 
allow it to evaporate while the operation is watched 
through the lens. For best results spread the drop 
of solution with the edge of a paper cutter or card into 
a thin film. A little practice will enable one to make 
a very uniform film in which the crystals form very 
beautifully. 

Of course the glasses must be perfectly clean. Per- 
fect cleanliness is absolutely essential in every part 
of microscopic work. Dust especially is the worst foe 
of the microscopist. It is well nigh impossible to be 
entirely rid of it, and every mote which remains is 
magnified by the higher powers into a beam. 

A bee furnishes a good object for dissection and 
preparation. The wings and the sting are especially 
interesting. The wings are provided with hooks de- 
signed to engage a rib on the other half. It is stated 
that no human being has ever been able to fasten the 
wings together. The feet and respiratory apparatus 
are also interesting. 

By a little labor one may dissect from a flower or in- 
sect interior parts of great interest. Indeed, it is by 
dissection that most objects are prepared for perma- 



liOMK MKCliAXK'S FO\l AMATEUKS 



iient preservation and use. The tools for tliis work are 
few and simple, and altlioni];li those sold by dealers 
are to be preferred, vet one may prepare for himself 
such substitutes as will enable him to do really good 




Fig. 212. A Practical Microscope. 

work. Our space does not allow much to be said upon 
this point. The indispensable articles are needles 
and knives. Dissecting needles are simply sewing- 
needles set in handles. Even a s])linter of wood or 



222 HOME MECHAXICS FOli AMATEUES 

wooden iienliolder answers all purposes of a handle, 
and the eye end of a needle may be pushed into it so 
as to be firmly set in its seat. Seyeral sizes of needles 
should be mounted ready for use. A small pointed 
blade of a penknife will answer for cutting. A yery 
suitable knife may be made by orinding the end of a 
needle to an edge and sharpening it on a stone. These 
tools though simple, are seryiceable. 

To dissect a flower, for example, place it upon the 
stage of the microscope and bring into focus Ayith the 
lens so that it is distinctly yisible. At first use the 
lens of longest focus. Then take a needle in each hand 
and open the flower, while you look into it. Obserye 
its petals, their colors, markings and hairs, if any are 
present, its stamens, their shapes and pollen, its seed 
vessel and any peculiarity. Many an exquisite yiew 
into Nature's most beautiful recesses is to be had in 
this way. So beautiful are many flowers that one feels 
it to be almost a profanation of a sacred shrine to ex- 
plore further. But still the unlocking of the shrine 
may disclose more profound mysteries, so we proceed to 
cut with one of our tiny kniyes across the seed yessel 
which occupies the center of the flower. Notice the 
symmetry of its arrangement, perhaps in three sections, 
else in four or fiye ; sometimes as many as ten rows of 
seeds may be found. It is a yery interesting point to 
study the arrangement and place of attachment of the 
seeds in the yessel. This mode of Ayorking is the mode 
used b}^ all botanists in their preliminary study of a 
plant. An entomologist studies an insect in the same 
way. 

After the limit of yision with the long focused 
lens is reached, a higher power is taken and the search 



HOME MECHANICS FOR AMATEURS 223 

is continued to the shortest focus the student may have. 
All of the ''coarse anatomy" of an ol)ject is studied 
by means of the dissecting microscope. The com- 
pound microscope inverts the view of an object so that 
a motion to the right seems to be toward the left, and 
towards, seems to be from one. It is very difficult to 
become accustomed to this inversion in dissecting, and 
for that reason the compound microscope is rarely used 
even by the most expert. Then, too, its field of view 
is small, and high powers are not needed in dissecting. 

The beginner is earnestly advised to study all sorts 
of minute things which he may find, since discoveries, 
surprises and most sublime views into the hidden 
things of Nature await him at every turn. A most 
useful book for this line of work is ''Common Objects 
for the Microscope," which the student is advised to 
buy. 

But with even the highest skill there is a limit to the 
use of simple magnifying glasses. The desire to know 
what lies beyond must be gratified in other ways. A 
compound microscope is the only instrument which 
will meet this condition and disclose all that can be 
seen by lenses. This consists of two lenses, one at each 
end of a tube, which is in two parts, one sliding Avithin 
the other. The lens nearest the object is the objective 
and is really a very fine simple microscope in itself. 
The upper lens, the eyepiece, increases the magnifica- 
tion of the objective and enables the eye when in the 
proper position to take in at once the entire picture 
produced by the instrument, and to study it in detail. 

The particular instrument shown in Fig. 211, 
although very plain and simple, is exceedingly well 
made, and very useful. It will receive the standard 



224 HOME MECHANICS FOK AMATEUES 

objectives and ej^epieces. It has a very smooth rack 
motion, which admits of very fine adjustment. The 
magnification of a compound microscope is varied by 
using- objectives of different focal lengths, eyepieces of 
different powers, and by changing the length of the 
tube. This microscope is usually provided with a half 
inch objective which may be separated to form a one 
and a half inch objective also, and an inch and a half 
eyepiece. 

If one wishes to put more money into the micro- 
scope he will next need a one-half inch eyepiece and a 
one-fourth inch objective. With these he will have six 
degrees of magnification at his command, varying from 
25 diameters to about 400 diameters. By diame- 
ters is meant the number of times broader an object 
appears. This is the usual mode of stating magnifica- 
tion. The number of times an object is magnified is 
found by multiplying the diameter by itself. Thus, 
if a seed is magnified fifty diameters it is made to ap- 
pear twenty-five hundred times its real size. 

A microscope of the value of this one should be 
handled with extreme care. There are certain simple 
points to be observed in the use and care of fine glasses. 
Never touch them Avith the bare fingers. It greases 
them and injures their transparency. Wipe them only 
with a very soft clean cloth, or bit of chamois skin. 
The glass of which the lenses are made is very soft and 
easily scratched. The finest dust may be composed 
of hard grit, which Avill leave its mark upon the lens if 
rubbed across it. It is Avell to blow the dust off be- 
fore wiping the lens. Lenses are easily broken if 
dropped. The most common accident is the dropping 
of tli(^ obj(M-tiA^e Avhile screwing it into its place or re- 






HOME MECHANICS FOE AMATEUES 225 

moving it. Even with care this sometimes happens. 
There is but one way of screwing or unscrewing the 
lens from the tube which is certain to prevent accident. 
Take the lens between the first and second fingers of 
the left hand, just as one would a cork or a lead pencil. 
Now hold it in the position to be screwed into the tube 
and turn it in wholh^ bv the right hand. Proceed in 
the same manner in unscrewing the lens. No accident 
can happen. 

With this microscope fitted with the half inch separa- 
ble objective and the one and a half inch e^^epiece an 
exhaustless field of study and delight is opened to its 
possessor. 



PART YII. 

ELECTRICITY 

A PRACTICAL PRIMARY BATTERY 

EVERY amateur who delights in "making things" 
dabbles more or less with electricity. Most of 
these are so situated that they have no access 
to the large sources of supply of the electric cur- 
rent, such as lighting stations can furnish, and if they 
would do any real work must make their own genera- 
tors and apparatus. It is to the assistance of such 
that the present section is devoted. 

The battery, represented by Fig. 213, can be made at 
a minimum cost, and when made will give a maximum 
of output. The materials to be purchased are glass 
jars, porous cups, carbons, zincs, burrs, screws, bind- 
ing posts and some sheet copper. 

All the pieces for the cell come ready for use, except 
the carbons, which are peculiar to the special form of 
cell. As the cut shows, there is a ring of carbons to be 
placed in the glass jar and to fit in the jar as closely as 
may be without exerting pressure upon the jar. Six 
plates of carbon are required for each ring. Each 
plate has two holes of a size to fit the screws. The 
holes may be made most easily by awls and reamers, 
such as are to be found in a set of tools in an awl 
handle. A little patience and experience will enable 
any one to make the holes neatly. Carbon is very hard 
and will wear a drill very fast. Hence, it is better not 
to attempt drilling holes in a carbon plate. Of course 
the holes should be equally spaced, if the appearance 
of the finished work is to be considered. 

[237] 



228 



HOME MECHANICS FOR AMATEURS 



The copper should be about l-32d of an inch in thick- 
ness and about f inch wide. It can be bought of 
this width, or cut by the dealer or by a smith with large 
shears. A strip must be bent into a six-sided ring of 
such size that when the carbons are fastened to it the 
whole will slide snugly into the glass jar. It will be 
better after one strip has been fitted to its place to 
straighten it out and use it as a pattern, or template, 




Fig. 213. A Practical Primary Battery. 



by which to drill the holes in the rest of the copper 
strips. They will then be all alike and interchange- 
able. A template should also be used for making the 
holes in the carbons, though all holes may be reamed a 
little on one side or the other to allow the screw to pass 
through. If the worker has no means of tapping a 
thread for the screw, he should buy nuts for the screws 
also. The holes in tlie copper strips may be punched 
with a nail punch, if one has no means of drilling them. 



HOME MECHANICS FOR AMATEUES 220 

For pimcliino' holes in this way the end of a stick of 
hard wood shonld be nsed as a bed to rest the copper 
upon ^A'hen punched. The strij) of copper which leads 
up out to the binding post may be riveted to the ring, 
or one end of the ring may be left long enough to bend 
up a couple of inches above the top of the jar. The car- 
bons should be long enough to reach above the jar so 
that the metal parts shall not touch the glass. In this 
battery the fluid employed will corrode metals very rap- 
idly. To prevent the fluid from creeping up through 
the pores of the carbon and reaching the copper, the 
ends of the carbons should be dipped in hot melted 
paraflftne and saturated by it before clamping them to 
the copper ring. 

The binding posts may be of any available form ex- 
cept those Avith wood screws. A machine screw is nec- 
essary because the binding post is to be clamped to the 
copper strip by it. When these parts are screwed to- 
gether the battery is ready to be assembled. 

Nothing has been said about the sizes of jars and the 
rest, since the cell may be made of a size to fit any jar 
into which the porous cup apd carbons will go. Round 
porous cups may be had from 1 J inches up to 5 inches 
in outside diameter, and round glass jars may be had 
from 2} inches up to 7 inches in inside diameter. There 
is thus ample range of size for any one to consult both 
the depth of his pocketbook and the quantity of current 
which he wishes the battery to give. This is a point 
not understood b}^ many amateurs. The voltage which 
a cell gives is determined by the kind of chemicals used 
in it and not by the quantities of chemicals consumed. 
The current in amperes, which, the voltage being fixed, 
the cell will give, and the work it can therefore do, are 



230 ITO.ArE .AEECHA^^rCS FOR AMATEIJES 

determined by tlie (luanlity of clieiiiicals consumed by 
the cell in its action. It nia}^ be stated as a fair aver- 
age result that one pound of zinc will give 320 ampere 
hours in a cell such as this. 

Carbon plates can be had in a great vaiiety of sizes 
and shapes. The best way is for the one contemplating 
making the battery to write to a dealer in electrical 
supplies and ask for a catalogue, which he will be glad 
to furnish. All the parts can then be selected of proper 
proportion to each other, so that they will go together. 
Either the Daniell, bottle or Fuller zinc should be us-ed. 
The cut shows the Daniell zinc. It is a good form be- 
cause of the large surface exposed to the action of the 
fluid. 

The best solution for this cell is the chromic acid 
fluid. It should be made by weight, taking chro- 
mic acid 18 parts, water 60 parts, sulphuric acid, con- 
centrated, 9 parts. A pint of water may be taken as a 
pound, and a pint of the sulphuric acid as 1.8 pounds. 
The chromic acid is a solid and can be most easily 
weighed directly. Put the chromic acid into the water. 
It dissolves readily. Then pour the sulphuric acid into 
the mixture very slowly, a little at a time, stirring it 
in thoroughly, else a disagreeable accident ma^^ be had 
from the heat produced. It is considered by many that 
this solution is improved by adding 1 part of chlorate 
of potash. When it is cold it is ready for use. 

The zinc in all cells of this character must be amal- 
gamated ; that is, coated with mercury. This may be 
done directly by dipping the zinc into the solution for 
a short time and then rubbing mercury upon it, or, bet- 
ter, by putting an ounce of mercury into the bottom of 
each porous cup. Another way is to add to the solu- 



HOME MECHANICS FOR AMATEURS 231 

tion in each porous ciij), as niiicli bisulphate of mer- 
cury as Avill lie on a quarter of a dollar. The zincs 
^Yill then be amalgamated directly from the solution. 

The cell may be set up in various ways with only 
slight differences in the resulting current, durability 
and constancy of action. \Ye will give four modes of 
arranging the cells : 

First — Fill the glass jar to within an inch of the top 
and the porous cup to the same level with the solution 
described above. 

Second — Fill the porous cup with a mixture of water 
10 parts and sulphuric acid 1 part, and the glass jar 
with the chromic acid mixture given above. 

Third — Fill the glass jar with the chromic acid solu- 
tion and the porous cup with water to which table salt 
has been added at the rate of 4 oz. to the pint. Sul- 
phate of zinc may be used in place of salt, 6 oz. to the 
pint. 

F;our — Fill the glass jar with chromic acid solution 
and the porous cup with clear water. This will start 
slower than any of the other modes of filling, but will 
work, because enough of the chromic acid solution 
passes through the pores of the cup to act upon the 
zinc. 

The adaptedness of this cell for many uses is shown 
by the fact that it can be arranged as a one fluid cell 
also. Removing the porous cup hang the zinc in the 
center of the glass jar by means of a board cover of the 
jar through which a hole is made to receive the end of 
the zinc. The fluid used will be the chromic acid solu- 
tion. The zinc must be fully amalgamated before put- 
ting it into service, and the bisulphate of mercury 
should be used to maintain the zinc in condition. In 



232 HOME MECHANICS FOR AMATEURS 

this form the cell gives its strongest current, but will 
only last about half as long. 

Whenever this cell is to be out of use the zinc should 
be removed from the liquid. The porous cup should 
be taken out and set in a dish of the same solution 
as it contains. In this way all waste of the chemi- 
cals is prevented. 

The battery, as described, is one of the strongest and 
most reliable primary batteries. With its strongest 
current it readily heats fine iron and platinum wires. 
With the porous cup it is adapted to drive motors, fans, 
and excite electromagnets. A large battery will light 
small incandescent lamps. Eight or ten cells, holding 
two quarts each, will drive the motor of Scientific 
American Supplement, No. 641, to full power, and run 
a sewing machine or turn a small lathe, or do any other 
equal work. The expense of maintenance is not great. 
The liquid when it becomes green is exhausted and 
must be replaced by fresh solution. The zincs can be 
used till they are entirely dissolved. This battery is 
not a toy, but a serviceable piece of working apparatus. 

ELECTRIC LIGHTING FOR AMATEURS 

It is now possible for any one to procure small incan- 
descent lamps from the Edison Lamp Co. and from 
most dealers in electrical goods. These little lamps 
can be operated quite successfully by means of easily 
constructed batteries. It is, of course, a little trouble- 
nome, and the expense of the electric light produced in 
this way is somewhat greater than other lights, but 
amateurs can derive a great deal of satisfaction from 
these experiments in electric lighting. 

The battery may be made at home, from materials 



HOME MECHAXICS FOR AMATEUES 



233 



that may bo purcliased from the manufacturers of the 
lamps or from any dealer in electrical supplies. Each 
cell of battery consists of two plates of carbon 2 in. 
wide, 4| in. long, and ^ in. thick, one zinc plate 2 
in. wide, 4 in. long, and i in. thick, two strips of wood 
i in. wide, ^ in. thick, and 4 in. long, two strong 
rubber bands, and an ordinary tumbler. 

The zinc is amalgamated by dipping it in dilute sul- 




FiG. 214. A Simple Battery. 

phuric acid (acid one part, water twelve parts), then 
sprinkling on a few small drops of mercury, rubbing it 
about with a swab formed of a piece of cotton cloth 
tied around the end of a stick. Every portion of the 
surface of the zinc should be covered with mercury. If 
the amalgamation is perfect, it need not be repeated. 
The carbon plates before use should each be heated 



234 



HOME :\rECHAXICS FOR AMxVTEUES 



at one end and satiirat(Ml witli paraffine for a distance' 
of 1:^ in. from the upper eud (and no more) to pre- 
vent the solution from ascending the plate by capillar- 
ity. This is accomplished by heating the end of the 
plate over a lamp and applying a piece of parafifine or 
a paraffine candle until it is filled. No free paraffine 
should be allowed to remain on the surface of the car- 
bon, as it will interfere with making a good electrical 
connection with the plate. 




Fig. 215. A Tumbler Battery. 



The zinc plate is placed between the two wooden 
strips. The carbon plates are placed outside of the 
strips and held b}^ the two rubber bands, as shown in 
Fig. 214. 

The connection between the carbon plates and the 
wire leading away from the carbon pole is made by a 
doubled strip, a, of copper, the ends of which are in- 
serted between the Avooden strips and the carbon plates. 
In a similar way a copper strip, h, is inserted between 



HOME MECHAN^ICS FOR AMxVTEITBS 



235 



the zinc plate and one of tlic wooden strips. Tlie 
tumbler forming the battery jar should be deep enough 
to allow the wooden strips to rest upon its rim, so as 
to support the plates a short distance from the bottom 
of the tumbler. 

The ordinary bichromate of potash solution is used 
in the battery. It is prepared by making a saturated 




Fig. 216. A Convenient Bracket. 

solution of common bichromate of potash in Avarm 
water ; then, after cooling, adding very slowly a quan- 
tity of common sulphuric acid, equal to about one-fifth 
of the bulk of the bichromate solution. It is advisable 
to add to the solution a very small quantity of bisul- 
phate of mercury, say one-eighth ounce to the quart of 
solution, to maintain the amalgamation of the zinc. 



236 



HOME MECHANICS FOE AMATEUES 



The salts known as tlie (\ k (\ battery e()ni])()nnd are 
excellent and very convenient for use in batteries of 
this class. It is only necessary to dissolve this com- 
pound in water to form the exciting solution. 

This material is sold in tin cans containing two or 
three pounds. It absorbs moisture rapidly, so that 
when it is to be used in small quantities it should be 
transferred to a stoppered glass jar. 

It is, perhaps, needless to say that great care should 




Fig. 217. A Series of Connected Lamps. 



be exercised in handling the solution, as it is poisonous 
and destructive to clothing, carpets, etc. The same re- 
mark applies to the battery compound. 

One cell of this battery should be allowed for each 
candle power of the lamp. The zinc of one cell should 
be connected with the carbon of the next. Fig. 215. The 
battery may be arranged as a plunger. Directions for 
making a battery of this kind were given on page 110, 
of volume 57, of the Scientific American. 



HOME MECHANICS FOR AMATEUES 237 

In Fig'. 216 is shown a convenient bracket for snp- 
porting small electric lamps. It consists of two cnrved 
wires attached to a small piece of board by means of 
screws, which also serve as binding screws for attaching 
the wires. The lamp is suspended from eves formed in 
the ends of the wires. This device may be used as a 
standard, as shown at 1, as a hanger, as shown at 2, or 
as a bracket, as at 3. 

In Fig. 217 is shown a series of three small lamps 
connected with three cells of battery. 

The lamps in this case are connected in parallel or 
multiple arc, i. e.^ one binding screw of each lamjD is 
connected with one wire from the battery. The other 
binding screws of the lamps are all connected with the 
remaining pole of the battery. 

Copper wire, No. 18 or larger, should be used for 
making the connections. The battery Avill run continu- 
ously with a single charge of the solution for about 
three hours. Should the solution become warm and 
give off hydrogen, the zinc should be reamalgamated at 
the points where it is violently attacked. 

THE ELECTRIC CHIME. 

To secure practice in mechanics or in electrical work, 
the amateur may as well construct something for 
actual use. A very useful and pleasing electro-me- 
chanical device is an electric chime to be used as a 
door bell or call bell, or in connection with a clock. It 
serves its purpose as a call and gives an ever-changing 
series of harmonic notes. 

The first step toward the construction of this device 
is to purchase the toy known as the tubophone, and 



238 



HOME MECHAXICS FOR AMATEUES 



select three of the tubes which produce a chord, or if 
the maker prefers it, he may buy a piece of mandrel 
drawn brass tubing, f inch external diameter, with 
walls sV inch thick, and cut off three pieces respectively 
7f , 8|, and 9| inches in length ; each of these should be 
laid upon two short pieces of soft woolen cord, with 




Fig. 218. Electric Chime. 



the cord touching at nodal i)oints, that is, at exactly 
one quarter of the length from the end. Arranged in 
this way the tubes give out a clear note when struck 
with a small wooden mallet. By comparing these notes 
with those of a piano or other musical instrument, the 
tubes may be tuned. The pitch is raised by shortening 



HOME MECHANICS FOR AMATEUES 239 

the tube, but as there is no practical way of lowering 
the pitch after the tube has once been shortened, it 
would be advisable to cut the tubes a little longer 
than the measurements given. A baseboard having a 
short standard is provided, and to the upper portion of 
the standard is secured a board into which are driven 
three pairs of wire nails, the nails in each pair corre- 
sponding in position Avith the nodes of one of the tubes. 
The tubes are suspended from these nails by soft 
cord.^ passing around the tubes at the nodes or points 
of no vibration, leaving the tubes free to vibrate at the 
center and at the ends. 

Now it remains to construct the electro-mechanical 
device for striking the tubes. To the baseboard are 
secured the angled ends of three strips of spring brass, 
^V inch wide and jV inch thick, which extend above 
the tubes and carry small wooden mallets in position to 
strike the middle portion of each tube. The mallets are 
secured to the springs by means of ordinary wood 
screws passing through the springs into the mallets. 

Behind the springs, at or near their mid-length, is 
placed a diagonal strip of wood, having secured to its 
outer edge a strip of felt or chamois skin. The spring 
strikes this piece and allows the mallet to strike the 
tube and spring back without jarring. Behind the 
springs is supported a small shaft on which is placed 
a wooden cylinder about 1 inch in diameter and 2^ 
inches long. In the cylinder and opposite the springs 
are inserted wire nails, arranged to strike short in- 
clined strips riveted to the springs. The nails are 
placed so that they will strike the inclined strips in 
different orders; for example: 1, 2, 3; 3, 2, 1; 2, 3, 1', 
1, 3, 2. 



240 HOME MECHA^nCS FOR AMATEURS 

A toy electric motor having a three-pole armature 
is used for turning the cylinder, and two clock wheels 
and a pinion are employed for reducing the speed. A 
worm is placed on the armature shaft of the motor, 
which engages the first of the clock wheels. This worm 
may be cut in a lathe, but if this is inconvenient, a 
wire may be wound spirally around the armature shaft 
and soldered. It will, of course, be necessary to wand 
the spiral so that it will fit the teeth of the clock wheel, 
and the surplus solder should be scraped from the wire 
to diminish friction. The motor is provided with bind- 
ing posts to receive the battery wires. One or two cells 
of dry battery will run the chime. The chime is used 
in place of an ordinary call or door bell, or it may be 
used in connection with a clock, as shown, for making 
calls at certain hours. 

The push button shown in the sectional view is made 
to close the circuit when the chime is used in place of a 
call bell or door bell. The button is readily made by 
boring a small block. A, of hard wood in two diameters 
to receive the head and back of the pearl collar button, 
B, the back of which is held in place by the apertured 
piece of veneering secured to the face of the block by 
small screws, while the head of the button rests on a 
curved brass spring, C, secured in a slot in the back of 
the block, A, by a screw. The outer end of the spring 
projects beyond the side of the block to receive one of 
the circuit wires. This slot is tilled below the spring 
with insulating material, and a brass plate, D^ is 
secured to the back of the block. A, and has upon one 
edge an apertured ear for receiving the other circuit 
wire. The plate, /), is secured to the back of the block 
by small screws. The free end of the spring, C^ is 



HOME MECHAXICS FOR AMATEUES 



241 



curved over to a point near the brass plate, Z), so that 
when the spring is depressed by pressing the button. 
By it will touch the plate and close the circuit. 

The annexed diagram shows an appliance which en- 
ables the chime to be used in connection with a clock. 




JD 

Fig. 220. 



Push Button. 



In front of the dial of an ordinary clock are secured 
the rings, A, B, made of tV inch square brass wire. 
The supports are of insulating material, and the rings 
are concentric with the arbor carrying the hands. The 
hands are bent outwardly to permit of extending over 
the rings without touching them, and to insure the 
hands against electrical contact with the rings a thin 
short sleeve of paper is slipped over each hand near the 
free end. Each ring has several small radial holes 
bored in it to receive the brass nails, the heads of which 
project sufficiently beyond the front surface of the 
rings to enable the hands to touch them as they pass. 

The circuit wires connecting the battery and the 
chime are connected one with the outer ring, A, the 
other with one of the springs of the cut-out switch 
shown in the opening formed by the breaking away of 
the dial. The other spring is connected with the inner 
ring, B. The springs are insulated from each other. 

On the sleeve which carries the hour hand is mounted 
the crossed slotted cam, O, also shown detached in the 



242 



HOME MECHANICS FOR AMATEUES 



larger figure. In the slot of this cam is a boat-shaped 
follower, which slides easily in the slot and is longer 
than the width of the slot, so that it can, in following 





FiiG. 219. Chime with Clock connection. 



the slot, take tlie inner and outer portions of the slot 
in alternation. The follower is pivoted to the angled 
lever, a, Avhicli is pushed by the cam between the jiar- 
allel springs and Avithdrawn from them in alternation 



HOME MECHANICS FOR AMATEURS 243 

once in 12 hours. The object of this arrangement is 
to cut out the chime at night and put it in circuit in the 
daytime. The cam, C\ and the angled lever, a, are 
insulated from the clock movement. 

A switch, D^ is provided for throAving the device out 
of action at any time. 

It will be seen that the hour hand must come into 
contact with the nail on the inner circle and the minute 
hand must touch the nail in the outer circle to com- 
plete the circuit, and cause the chime to sound. The 
duration of the chiming is limited by the time the 
minute hand is in contact with the nail. The clock 
when arranged as here shown sets off the chime at 8 
o'clock, 12 o'clock and 5 o'clock. It is now about to 
ring the chime for 12 o'clock. 



HOME-MADE ELECTRIC NIGHT LAMP 

A very simple device, Avhich will produce a temporary 
light of one-half of one candle-power, is shown in the 
illustration. It will be found convenient for observing 
the time at night, or for momentarily lighting a closet 
or an area where the light of a candle or an oil lamp 
would be objectionable. 

The miniature electric lamp, and the dry batteries 
used for lighting it, can be purchased almost an^^ where, 
and the labor of putting these things together, with a 
switch and suitable connections, is very slight indeed. 
A one-half candle lamp requiring 1.58 amperes at 2.5 
volts is the first requisite; then two cells of dry battery, 
giving a current with a pressure of al)out 3 volts will 
be needed, and last of all a small packing box, that will 
just receive the batteries, should be selected. If a 



244 HOME ]\IECHANICS FOR x\MATEITES 

lamp of liii>her voltage is chosen, more cells of battery 
Avill be needed. A 4-yolt lamp Avill require three cells 
of battery. A little more light will be secured with this 




Fig. 221. Battery Box, cover removed. 



^■ 




■-^ 




^^ .-..-.»« 


\ 








WmmM 


gggl^HBIHjIg^^^ 


n 



Fig. 222. Temporary Light. 



combination, but it is not desirable to increase the num- 
ber of cells beyond this, as the apparatus becomes at 
once too bulky and too expensive. The best cond)ina- 



HOME MECHAXICS FOR AMATEUES 



245 



lioii is the one-half candle lamp will two cells of bat- 
tery. After the lanip is procnred it slionld be tested mo- 
mentarily' by means of two cells of dry battery, con- 
nected in series. If the lamp is properly lighted, a 
packing box which receives the batteries easily is se- 




FiG. 223. Diagram of Circuit. 

lected, and two small brass hooks, / cj, are straightened 
and screwed into the box near the top. Small copper 
wires are placed in electric contact with the hooks, f ()y 
as sliOAvn in the diagram. At the top of the box is 
placed a switch, consisting of a piece of spring brass 3 
inches long and ^ inch wide held in place by a pivotal 
screw, e, passing through a central hole in the spring 
into the box. 

In one of the views the lamp is represented as being 
supported by a hollow Avooden column in front of a 
clock. In this case one of the lamp wires is incased in 
a very small rubber tube, to insure insulation ; other- 
wise the construction is similar to that described. 

Two cells of dry battery will light the lamp occa- 
sionally for a long time, if used only an instant each 
time; but if the lamp is used continuously, it runs the 
battery down, so that it will require frequent renewal. 

The wire from the brass hook, /, is placed in electrical 



246 HOME MECHxlXICS FOR AMATEURS 

contact with this screw, c, and two brass screws, b c, 
are inserted in the top of the box, to serve as contact 
points for the switch. These screws are connected to- 
gether and with the zinc pole of the cell, n' , by a wire. 
The carbon pole of the cell is connected electricalh' 
with the hook, //. The hooks are curved downwardly 
and the terminals of the lamp, ii, are wound three or 
four times around the ends of the hooks, / g, respec- 
tively, so as to support the lamp above and in front of 
the face of the watch, hanging' upon the hook, project- 
ing from the front of the box. 

The longer arm of the switch is turned up to form 
a thumb piece, and is held normally out of contact 
with the screw, h. By pressing the end of the switch 
down into contact with the screw, h, an electrical con- 
tact is formed which lights the lamp. By turning the 
switch on its pivotal screw, e, it is brought into contact 
with the screw, c, thus forming an electrical contact, 
Avhich is prolonged until the switch is returned to its 
original position. The movement of the switch is 
limited by the screws, d d. 



AN ELECTRICAL CABINET 

An electrical cabinet is an assemblage of articles 
which may be combined in various ways to produce 
pieces of apparatus. By these a large number of ex- 
periments are made accessible to the amateur at com- 
paratively slight expense. 

In Fig. 224 sectional drawings of the essential parts 
are shown, drawn very nearly on a third scale. A are 2 
coils, wound with 8 layers of No. 20, single cotton cov- 
ered magnet wire, both being wound in the same direc- 



HOME MECHANICS FOE AMATEURS 247 



tion. B, the cores and yoke of an electromagnet, the 
cores of f| inch soft iron bar. C, the frame for support- 
ing the electromagnet when used as the field coils of a 
dynamo or motor as in Fig. 237. D, a wooden stand, 
turned in a lathe, to be used as a support for the com- 




FiG. 224. General View of Parts. 

pass E, to form a galvanometer, as in Fig. 229. F, a 
permanent horse shoe magnet. G, soft iron wires. 
H, strips of copper. K, frames for telegraph sounders. 
By the aid of the Figures for the several experiments 
the practical amateur will have little difficulty in see- 



248 HOME MECHANICS FOE AMATEUES 

ing how tliev are made and put to<^ether. The perma- 
nent magnet and the compass can be purchased to bet- 
ter advantage. The rest can be made with a lathe 
and tools. Some No. 28 spring brass wire will be 
needed for the springs shown on the telegraph sounder 




Fig. 225. 
Effect of Iron on a Magnet. 




Fig. 226. Decomposition of Water. 



at the left, and some No. 18 spring brass wire to be 
wound into a close spiral a little less than a half inch 
in diameter, and cut up into pieces of about 3 turns 
each to be used as connectors in place of binding posts. 

In describing the several experiments such addi- 
tional instruction will be given as the case may seem 
to require. 

The action of iron on a magnet is shown in Fig. 225. 
Present the end of an iron rod to the compass. The 
needle is drawn towards the iron and swings till it 
points directly towards it. The magnet F may be used 
for this experiment. The north or marked end of the 
magnet repels the north end of the needle and attracts 
its south end. As we say, like poles repel, unlike at- 
tract. The brass and glass cannot stop the attraction. 
Paper, wood, anything except iron, may be interposed 



HOME MECHANICS FOR AMATEURS 



249 



betweeu the magnet and the needle without destroy- 
ing the attraction and repulsion. 

The decomposition of water into two gases, oxygen 
and hydrogen, by electricity is a very interesting ex- 
periment. For its best exhibition platinum is required, 
but as this is a very expensive metal a method is given 
by which one gas can be produced. Fig. 226 gives the 
arrangement of the apparatus. The light and heavy 
parallel lines indicate cells of battery. Two at least 
are required. A good form of cell is represented in 
Fig. 229. The glass is a common tumbler. Two plates 
of battery carbon and one of zinc are clamped together 
by two bolts which pass through the four strips of 
wood. Strips of sheet copper or brass, d and e, are 
included between the strips; d is cut long enough to 





Fig. 227. Galvanometer. 



Fig. 228. Electroplating. 



connect with both carbon plates. Two of the spirals 
described above are pushed on these strips to receive 
the copper wires used in forming the circuits. This 
sort of connector is nearly as good as a regular binding 
post and costs a mere trifle. 



250 



HOME MECHANICS FOR AMATEUES 



The fluid for the cells is made by dissolving in cold 
water as much bichromate of soda as the water will 
take up, and adding slowly and with constant stirring 
one-tenth of the yolume of sulphuric acid. The plates 
should only remain in the solution while they are in 
actual use. 




Fig. 229. Detector Galvanometer. 



The tumbler shown in Fig. 226 is to be filled with 
water and a little sulphuric acid added. Lacking the 
acid, vinegar may be used in its stead. 

With two cells fine bubbles of h^^drogen gas come off 
slowly from the copper which is attached to the wire 
leading from the zinc of the battery and rise to the 
surface. The oxygen combines with the copper and 
does not appear as a gas at all. If platinum were used 



HOME MECHANICS FOR AMATEURS 



251 



for the other strip oxygen would be giveu off from its 
surface, since oxjgen does not combine with phitinum 
under these conditions. This most interesting experi- 
ment was first performed by Sir Humphry Davy many 
years ago. 

Fig. 227 shows how^ to arrange one of the coils A, 
the compass E, the support D, and the battery as a 
galvanometer. Place the coil so that its length is east 
and west and place the compass over the coil. The 
needle will lie crosswise of the coil. When the current 





Fig. 230. Sucking Coil. Fm. 231. Lines of Magnetic Force. 

flows the needle is turned from its north and south 
position. The laws and meaning of this is explained 
fully in the text books of electricity. 

Electroplating has become one of the most important 
industries. It can be performed with the apparatus of 
Fig. 228. The arrangement is the same as that of Fig. 
226, except that the tumbler is now to be filled with a 
liquid containing the metal with which the article is 
to be plated. To plate wnth copper a solution of copper 
sulphate may be used, though carbonate of copper is 
better; for nickel a double carbonate of nickel and 
ammonia is used. The metal will be deposited on the 



252 



HOME MECHANICS FOR AMATEURS 



strip attached to the wire from the zinc, that one on 
Avhich the hydrogen appeared when water was decom- 
posed. The other strip must be of the metal with which 
tlie plating is to be done. 




Fig. 232. Mode of Inducing an Electric Current by a Magnet. 

More instruction and much experience will be re- 
quired for real work; but much pleasure can be de- 
rived by watching the process in this simple manner. 
Three or four cells should be used for depositing nickel. 

If a copper wire is passed straight through the fix- 
ture D, and the parts are set up as in Fig. 229, it will 
constitute a detector galvanometer, suitable for large 
currents, as the arrangement in Fig. 27 is adapted for 




Fig. 233. Mode of giving an Electric Shock. 

feeble currents. The wire in all cases must be placed 
north and south, or lengthwise of the needle when at 
rest. 

The uses for an electromagnet in experimenting are 
very many. It is the most important piece of electrical 



HOME MECHAXICS FOE xVMATEURS 253 

apparatus, and was invented by Sturgeon of England 
and also by Prof. Joseph Henry in America. Probably 
neither knew the work of the other. Henry's inven- 
tion led directly to the electric telegTaph. Fig. 230 is 
given as an illustration of the power of a helix to draw 
iron or steel into itself. If a strong battery is used 
the pen is sucked into the coil with considerable force. 
A large number of small Avire nails may also be held 
up in the coil without visible support. It is wizard- 




FiG. 234. Microphone. 

like to see a piece of heavy metal hanging in the air 
upon nothing. Numerous modifications of this curious 
experiment will suggest themselves to an ingenious 
person. 

With the two coils A, put upon a U-shaped iron 
rod f inch thick, as in Fig. 231, the beautiful mag- 
netic phantom or magnetic field of force can be made 
visible. The wires from the spools are connected to 
the battery, which is not shown. Join the two spools 
together so that the outside of the winding of one is 



254 HOME MECHANICS FOR AMATEURS 

connected to the inside of the winding of the other. A 
thin board is laid over the poles and iron filings sifted 
over the board. Then tap the board gently with the 
tip of a finger. The filings jump with sudden alac- 
rity into lines, definite and exact. The figure shows 
these lines. It means magnetic attraction. Now 
change the connections. Join the two outside wires of 
the spools to the battery and the inside Avires to each 
other. The figure changes to one exhibiting repulsion. 
The lines shun each other. 

If blue print paper be pinned on the board and the 
whole exposed in the sunlight, fine photographs may 




Fig. 235. Electromagnet for Lifting. 

be made of these beautiful figures. By using horse 
shoe and bar magnets, endwise and flatwise, a great 
variety of magnetic fields may be mapped. 

Next arrange the apparatus as in Fig. 232. The 
compass needle is strongly defiected from its north and 
south position. Now remove the battery and close the 
circuit. Plunge a bar magnet into the right hand coil. 
The needle swings, though not so strongly as before. 
An electric current is generated so long as the magnet 
is in motion, either in or out of the coil. 

If the cores of the coils in Fig. 232 are filled with 
iron Avires a current may be generated by simply tak- 



HOME MECHAXICS FOR AMATEUES 



255 



iiio- the right hand coil in the hands, holding it north 
and sonth and turning it over quickly. These effects 
Avere discovered by Ampere, for whom the unit of cur- 
rent is named. The student should look up the subject 
in text books of electricity. 

The giving of electric shocks to one's friends is al- 
ways a pleasant pastime. One mode of doing this is 
illustrated in Fig. 233. Of course no severe shock can 
be given in this way. The metal handles of Fig. 238 
should be connected to the open ends of the wires to 




Fig. 236. Electric Telegraph. 



the left. Scrape the ring along the file and a slight 
shock will be felt by one who grasps the handles with 
moist hands. The shock is produced by an induced 
current. The arrangement is a very simple form of 
induction coil. As the making of a strong coil is a 
difficult matter, a special and full description of the 
coil to be made should be obtained before undertaking 
such a piece of work. 

Fig. 234 is a microphone. Two bits of iron wire, or 
bright wire nails, p, are connected to the Avires and laid 



250 



HOME MECHAXICS FOR AMATEUES 



on the top of a box made of thin wood as shown. Pine 
is to be preferred. A sheet of iron is laid upon the top 
of the electromagnet. On tapping the box gently a 
much louder sound will be heard from the sheet of 
iron, when all is working well. This effect is the basis 




Fig. 237. % Dynamo or Motor 



of the invention of the transmitter of the telephone. 
If a telephone receiver is used in place of the electro- 
magnet and sheet of iron, the feeblest sounds produced 
on the top of the box are greatly intensified. The 
microphone box may even be used as a telephone trans- 
mitter if the wires are long enough to permit it to be 
placed in another room, and all the parts are suflfi- 
ciently delicate. 

The arrangement of an electromagnet for lifting pur- 
poses is shown in Fig. 235. By means of a spring 
balance one may find the pull necessary to remove the 
armature when the number of cells of the battery is 
varied from one cell up to its full capacity. The iron 
bar used as an armature should always be as large in 
cross section as tlie iron core of the magnet. 



HOME MECHAXICS FOE AMATEUES 



257 



Fig. 236 will guide one in setting up a telegraph line, 
with a station at each end. The key is simply a strip 
of spring sheet brass. When not in use it is pressed 
down and caught under the head of the screw beyond 
it so as to close the circuit. The construction of the 
sounder is so simple that it will not be given in detail. 
The most diflticult part to adjust is the vibrating arm, 
m, whose blows against the slot in the post to the right 
produce the sound Avhich gives the name to the instru- 
ment. The vibrating bar should not strike the electro- 
magnet A\'hen it is pulled down, nor have a very Avide 
range of motion. The bar must either be wholly of 
iron, or better, have a block of iron riveted to it, since 
brass is not attracted by a magnet. The tension of the 
tine wire spring on the left determines the force neces- 
sary to pull the bar down. 




^^^^^"^^^ 



Fig. 238. Shocks by Rotating Coil. 

To work the telegraph swing the key from under the 
head of the screw which holds it down. This opens 
the circuit. The bar of the sounder flies up. Now^ 
press the key down till it touches the wires below it. 
The current from the battery flows and the armature 
is jerked down, giving a sharp blow on the post which 
detains it. As the key is moved down and up the arma- 



258 HOME MECHAXICS FOE AMATEUES 

tiire moves clown and up, produciug the clicks which 
all have heard in a telegraph office. 

By getting a Morse alphabet and mastering the art 
of producing dots and dashes two persons may soon 
learn to send messages to each other. 

A model of a dynamo may be built from the parts, 
A, B and C, of the cabinet. This is shown in Fig. 237. 
The electro-magnet formed by A and B is fixed upon C, 
and the circuit completed by short pieces of magnet 
wire. The open ends to the left may be connected to 
the galvanometer, I) and E, to detect the current. 

The rotating coil, H, and the commutator J, are 
somewhat difficult of construction. The coil consists 
of about 100 turns of No. 20 single cotton-covered 
magnet wire. The inner end of the wire is soldered to 
one of the half rings of the commutator, the outer end 
to the other half ring. 

On whirling the coil rapidly a feeble current will be 
produced. The current will be reversed, if the coil is 
whirled in the opposite direction. 

This tiny dynamo may be transformed into a series 
Avound motor by connecting the battery in place of the 
galvanometer. 

By changing the connections as shoAvn in Fig. 238, 
the electric current may be felt in the handles when the 
armature is whirled rapidly. 

Though the experiments described by no means ex- 
haust the subject, nor the resources of the electrical 
cabinet, still they place before the studious amateur 
enough to employ many an hour most profitably, and 
to incite him to further study and to higher work. 



HOME MECHAmCS FOR AMATEURS 259 

SIMPLE ELECTRIC MOTOR 

Almost every youug amateur mechanic is desirous 
of making something having the ability to move and 
show action. An electric motor does this; and while 
the mechanic is making a good piece of machinery, 
he is also learning the principles of electricity^ 

The motor we shall describe is intended to turn a fan 
or light machinery by means of a current derived from 
a battery. It will drive a light sewing machine or 
other machinery requiring a similar amount of power, 
and it is so simple as to admit of being constructed 
with the tools ordinarily possessed by an amateur. 

To begin a motor at the right i)oint is very import- 
ant. The first thing to be done is to construct the 
armature — the part which revolves. On account of its 
simplicity, Ave have selected the Gramme armature. 

The core of this armature consists of a ring formed 
of No. 24 sheet iron. A strip f inch wide and 8 feet 
long (the length of a sheet) is carefully cut from the 
sheet and wound upon a cylindrical piece of wood in 
the lathe or by hand. The wood cylinder is If inches 
in diameter and 1 inch thick, and in the edge is cut a 
shallow notch of a depth equal to the thickness of the 
sheet iron, as shoAvn in Fig. 240. In the iron, | inch 
from the end is drilled a hole, countersunk to receive 
a wood screw, which passes through the sheet iron 
into the wood, and fastens the end in the notch in the 
wood. The sheet iron thus attached to the wood may 
be wound closely around the wooden mandrel without 
a kink being formed by the inner end of the strip, 
which is in the notch. 

Before beginning the winding, a piece of strong an- 



260 



HOME MECHANICS FOE AMATEUES 



nealed wire, stove-pipe wire for example, is placed in 
a handy position, and when nine layers of the iron 
have been wound the strip is cut off and the binding- 
wire is wrapped around the coil and twisted together 
at the ends, to keep the sheet iron from unwinding. 




Fig. 239. Electric Motor. 



The wood and the coiled sheet iron are together 
removed from the lathe (or vise if it is being done by 
hand), and placed in a fire, which will heat the iron 
to a cherry red and bum out the wood. The ring is 



HOME MECHAXICS FOE AMATEURS 261 

then covered Avitli ashes and allowed to cool slowly. 
This anneals the iron, and improves its magnetic per- 
meability. 

After removal from the ashes, and while the binding 
wire is still in place, the ends are secured by passing 
rivets through them ; the inner end, which was bent, is 
cut off, and the ends are beveled with a tile, and all 
the sharp corners are reduced by the same means. 

The core of the armature is then covered with adhe- 
sive tape (either electrical or bicycle tire tape), when it 
is reafly to receive the magnet wire with Avhich it is to 
be wound. The ring is divided into five equal sec- 
tions, and marked with a pencil to show how much 
space each coil of the armature is to occupy. There 
are five coils on the armature, Avitli five layers in each 
coil. No. 21 single or double cotton or silk covered 
wire is used. It requires about 28 feet of wire for each 
coil. The winding is a, slow and rather laborious 
process. The length of wire for a coil is wound on a 
sort of shuttle-stick f inch wide, 12 inches long, with 
a notch in each end. The end of the wire is wrapped 
twice or three times around the ring over a piece of 
stout thread, which is tied around the wires to fasten 
them together, to begin a coil. Of course, the begin- 
ning is at one of the marks on the ring. 

Now the shuttle is passed through the ring and 
brought back over the outside until one layer covers 
one space; then commencing the winding over the 
first layer the second is laid on, then the third, fourth, 
and fifth; all the layers are wound in the same way. 
The last three or four turns are made over a stout 
thread, which is tied when the last convolution is 
made. 



262 HOME MECHANICS FOE AMATEUES 

The other coils of the armature are made in the 
same way, and when tlie winding is all on, the end of 
one coil is twisted with the beginning of the adjacent 
coil. A piece of well seasoned hard wood, hard maple, 
for example, is bored to receive a piece of A inch drill 
rod — Stubs or something equally good — which consti- 
tutes the shaft. This rod is 4 inches long. A tV inch 
hole is drilled transversely through it at or near the 
center to receive a short pin which enters a slot in the 
end of the Avooden hub. 

This piece of wood is turned to fit the interior of the 
armature, and is cut off about the same length as 
the armature. The coils of the armature and the 
wooden hub are now varnished with thin shellac var- 
nish, and allowed to dry thoroughly. The armature 
ring is then slipped into its place on the wooden hub, 
and the hub and the ring are coated with two coats of 
shellac varnish, one coat being allowed to dry before 
applying the other. 

The next thing to claim attention is the commutator. 
This is a core of wood fitted to the armature shaft and 
turned to fit a piece of brass or copper tube f or f 
inch in diameter and f inch long. This tube is divided 
into five divisions, and parallel lines, preferably slightly 
spiral, are drawn from the divisional points marking 
the places where the tube is to be sawed to form the 
commutator bars. But before sawing, each end of 
each space which is to form a bar is drilled, and the 
hole is countersunk to receiv^e a small wood screw, 
which passes into the Avood and holds the bar in 
place when the brass tube is sawed on the lines to 
separate the bars. After salving, the commutator is 
turned smooth and round, or filed in the lathe with a 



HOME MECHANICS FOE AMATEURS 263 

smooth file. The screws used in fasteniiii;' the commu- 
tator bars must not touch each other or the shaft. 

The twisted teniiinals of the coils are now stripped 
of the winding at the ends and soldered to the commu- 
tator bars, having been cut off the proper length to 
reach to the commutator. 

Before soldering, however, the ends of the terminals 
and a small portion of each commutator bar are tinned 
to facilitate the work of soldering. To tin the copper 




Fig. 240. The Armature Core. 

wire, a little pulverized rosin is rubbed on the ends of 
the wires, and the solder is applied with a soldering 
iron. 

The commutator bars are tinned for J inch at the 
ends nearest the armature ring in the same manner. 

The terminals of the armature coils are bent so as 
to touch the commutator bars at the tinned surfacef^; 
the beginning of one coil and the end of the adjacent 
coil being thus brought into contact with a commutator 
bar. They are then soldered by applying a drop of 
solder by means of the soldering iron. The wires are 



264 HOME MECHANICS FOE AMATEUES 

thus made to answer tlie double purpose of conveying 
the current to the commutator bars and of causing the 
commutator to revolve with the armature. Acid must 
not be used in soldering electrical connections. 

To run smoothly, the armature must be in balance. 
To ascertain whether it is in balance, place the arma- 
ture shaft on the edges of two level straight-edges sup- 
ported about 4 inches apart. If the armature will 
stand in any position, it is balanced. If it rolls so that 
one side after a few oscillations of the armature goes to 
the bottom, the top must be made heavier to counter- 
balance the bottom. Probably the best way to add 
weight to one side of the armature is to apply it in the 
form of solder to a band of wire about f inch wide 
wound around the armature. Before this winding is 
applied, a strip of mica f inch wide must be wrapped 
around the armature and secured in place by shellac 
varnish applied to both the armature and to the mica 
and allowed to become nearly dry. It is not necessary 
to use a continuous piece of mica ; it may be in several 
pieces. When the armature comes to rest after oscilla- 
tion, solder should be applied to the upper side of the 
wire band until the armature will stand in any posi- 
tion. If too much solder is applied, the surplus may be 
removed by a coarse file. It is important to have the 
armature as nearly in balance as possible. It will then 
have very little vibration, or none at all, while running 
at any reasonable speed. 

Care should be used in all the operations connected 
with this motor to insure entire success. 

The next thing to be done is to construct the field 
magnet, which in this motor is in the form of a ring, 
as shown in Fig. 241. The core of the field magnet is 



HOME MECHANICS YOU xVMATEUES 



265 



formed by wiuding four strips of No. 24 sheet iron f 
inch wide and 8 feet long upon a wooden core, as in the 
case of the armature core. The form on which the 
field magnet is wound being A inch larger in diameter 
than the armature, and as this is variable, it must be 
ascertained after the armature is wound and balanced, 
on account of the variation in the winding depending 
on the covering of the wire and the care with which it 




Fig. 241. Field Magnet Core. 



is wound. In the motor illustrated, the field magnet 
ring is 2f inches internal diameter and 4^ inches ex- 
ternal diameter. Before winding the field magnet core, 
the ends of the 8-foot strips are scarfed or beveled off 
and tinned, and then soldered together and coiled for 
convenience. 

The strips should be wound upon the form as tightly 
as possible, and when the last layer is on, a stout wire 
is wrapped around the outside and twisted together to 



266 HOME MECHANICS FOR AMATEUES 

keep the sheet iron strip from imwiiKliuij^, as in the 
case of the armature core. 

As it is not necessary to anneal the field magnet, the 
wooden form is removed by boring a hole through it 
and then splitting the Avood so that it can be removed 
piecemeal. The coil of sheet iron forming the field 
magnet core is composed of thirty-three layers. 

The ring is divided into four quarters by radial lines, 
and midway between two of these lines, on opposite 
sides of the ring, are drilled holes for rivets A inch in 
diameter, the holes being countersunk slightly on each 
side. These rivets with slight heads are inserted in 
the holes, with the heads inside the ring. They are 
then neatly riveted at the outside, leaving the inner 
side as smooth as possible. To accomplish this, it is 
necessary to move the binding Avire away from the 
center of the field magnet ring. 

When the two riAT^ts are in place, the binding Avire 
may be remoA^ed; then in the same sections near the 
ends are placed rivets, one at each end of each section. 
The sections riA^eted in this manner form iuAvardly 
projecting pole pieces. While drilling the holes for 
the riA^ets, it is necessary to clamp the strips firmly to- 
gether to prevent the drill chips from Avorking in be- 
tAveen the layers of the magnet. Eleven layers of the 
magnet ring are sawed out between the pole pieces to 
make a space for the Avinding of the field magnet ; the 
ends of the pole pieces are bcA^eled as shoAvn to facili- 
tate winding. These spaces are covered with adhesiA^e 
tape and are wound with four layers (about 45 feet) of 
No. 18 magnet wire, either single or double, cotton or 
silk covered. 

One of the pole pieces will be at the bottom of the 



HOME MECHANICS EOE AMATEUES 



267 



field iiiai»uet and the other at the top when the motor 
is conipk'te; tlierefore the winding on eaeh side of 
tlie fiehl magnet l)egins at opposite sides of the same 
pole piece, and is wound in the same direction to bring 
the wire terminals near the base of the machine, and 




Fig. 242. Electrical Connections of Motor. 

to cause the current in the two windings to unite in 
producing a north pole at the top of the magnet and a 
south pole at the bottom, or vice versa. If a mistake 
is made in the winding, this can be corrected in making 
the connections. It is not necessary to unwind and 
rewind. 



268 HOME MECHANICS FOE AMATEUES 

The constriictiou of this magnet is open to criticism 
on account of the disposition of the laminae, but this 
construction is partly or wholly compensated for by the 
large rivets, which bind the pole pieces and the body 
of the magnet together. 

The holes are drilled in the lower side of the magnet 
and tapped to receive machine screws, which pass up- 
ward through the base of the machine to hold the 
magnet, which latter sits upon a small wooden saddle 
about I inch thick in the middle. The field magnet 
winding, as well as the iron core, is covered with sev- 
eral coats of shellac varnish, for insulation and protec- 
tion. 

The journal boxes for the shaft are simply f brass 
balls axially bored to receive the shaft, and having an 
oil hole in the top. These boxes are each held in place 
by two brass plates bored to receive the sides of the 
balls as shoAvn, and attached to the sides of the square 
wooden standards by screws. The shaft is allowed to 
project at one or both ends sufficiently to receive a 
pulley or fan. The armature is wrapped around the 
sides with enough firm paper to cause it to fit tightly 
into the field magnet, and after the shaft is made level, 
the journal boxes are placed on the shaft, and the 
standards which support them are sawed off the prop- 
er length and secured to the base by scrcAVS, one for 
each standard, passing upwardly through the base and 
into the lower ends of the standard. To the base ad- 
joining the standard at the commutator end is attached 
a wooden block, to the ends of which are secured light 
copper springs, which bear on opposite sides of the 
commutator and act as brushes for conveying the cur- 
rent to the armature. 



HOME MECHANICS FOR AMATEUES 269 

The screws Avliich hold the lower ends of these 
brushes also clamp the wires which extend downward 
through the base, one being connected with one of the 
binding posts which receive the battery wires, the 
other brush being connected with the outside terminal 
of one of the field magnet coils. The outside terminal 
of the other field magnet coil is connected with the re- 
maining binding post. The inside terminals of the 
field magnet coils are connected together. The con- 
nections are clearly shown in the diagram (Fig. 242). 
The upper screws in the commutator brushes are used 
for varying the pressure of the brushes on the com- 
mutator as may be required; the brushes being bent 
outwardly to admit of this adjustment. 

If the motor is to be used for driving a fan, the base 
will need to be set upon legs of some kind. In the 
motor illustrated, the base is supported upon four in- 
verted clothes hooks which support it 2 inches from the 
table. 

The oil cups are made of wood (soft maple or birch), 
with stems extending down into the fV holes in the 
spherical boxes; and in the portion of the wood above 
the journal box is formed a cavity which will contain a 
few drops of oil. The outside of the oil cup is varnished 
with shellac except at the end of the stem, before any 
oil is put in. This confines the oil to the cavity and 
the interior of the stem and causes it to slowly feed to 
the journal on which the stem rests. The fan can be 
purchased for a small sum. It may be necessary to 
bush it to fit the shaft. Either an 8-inch or a 10-inch 
fan may be used. 

Of course, a small pulley will be substituted for the 
fan when the motor is used to drive a machine. 



270 HOME MECHANICS FOR AMATEURS 

If the motor Avlien finished does not rnn in the de- 
sired direction, this may be changed by transposing the 
wire connections at the brushes, so as to change the 
direction of the current in the armature. 



SMALL ELECTKIC MOTOEiS FOK AMATEURS 

Every piece of electric work done by a student or 
amateur is of value, not only as an addition to his 
collection of apparatus, but as a means of acquiring a 
positive knowledge of electricity and of electrical appa- 
ratus. The following engravings show a simple and 
easily constructed motor, which very fully illustrates 
the construction and operation of the Gramme motor, 
and is well adapted to various uses requiring only a 
small amount of power. 

This motor was built by Mr. W. S. Bishop, of New 
Haven, Conn., after the general plans of the simple 
electric motor already illustrated and described in a re- 
cent Scientific American, but the construction here 
shown is more simple and more easily carried out. 
The perspective view here given is two-thirds the 
actual size. The front and side elevations and the 
smaller detail view are full size. 

The field magnet. A, is formed of a yoke of Norway 
iron -f-Q inch thick, ^ inch wide and 2^ inches long. 
In the yoke, near its ends and lA inches apart, are 
drilled holes for receiving the quarter inch Norway 
iron cores of the magnet, which are driven into the 
yoke. 

The polar extremities, a, of the field magnet are 
curved to form a circular opening 2tV inches in diam- 
eter. The winding of the field magnet may be applied 



HOME MECHAXICS FOE AMATEUES 271 

to the magnet cores, as shown in the engraying, or the 
wire may be wound npon spools fitted to the cores. 
The spools are 1 inch in diameter and 1 J inches long be- 
tween the heads. Upon each spool is wound 1 ounce of 
No. 24 double wound, cotton covered magnet wire. The 
yoke of the field magnet is fastened to the wooden 
base piece of the motor by screws passing upwardly 
through the base into threaded holes in the yoke. 

The armature, B, consists of a small Gramme ring 
mounted upon a wooden disk secured to the armature 
shaft. The armature core, c, is a ring formed of a piece 
of annealed iron wire. No. 13 B. & S. gauge, having its 
ends beveled and drilled transversely to receive a pin, 
as shown in Fig. 246. A core of this kind, although 
theoretically not as efficient as a laminated core, 
answers every purpose in this very small motor, and 
greatly facilitates the construction of the armature. 
The core has an outside diameter of If inches. The 
outside diameter of the armature is 2 inches, and the 
inside diameter IJ inches. Upon the armature core 
are placed 12 coils, h, of silk covered, single wound mag- 
net wire. No. 25 B. & S. gauge, separated by rings d of 
soft iron Avire No. 13, the rings forming polar exten- 
sions which add to the efficiency of the motor. The 
armature coils are formed in a lathe on a mandrel, 
separately, as shown in Fig. 247. This mandrel con- 
sists of a piece of No. 11 wire having two collars f of an 
inch apart, one of the collars being fixed and the other 
being removable. Each coil contains 4 feet 4 inches of 
wire wound in five layers. 

To facilitate the removal of the coil from the man- 
drel, the first layer is wound loosely. After winding, 
and before removing the coil from the mandrel, the Avire 



272 



HOME MECHANICS FOR AMATEURS 



is cemented with paraffine or wax melted on the coil 
with a warm iron. After twelve coils have been com- 
pleted, they are strung upon the armature core, c, in 
alternation with the iron wire rings, d^ and when the 




Fig. 243. Perspective View of a Small Gramme Ring Motor. 



core is filled, its ends are brought together and secured 
by means of the pin, as shown. 

The Avooden liub of the armature is now fitted to tlie 
ring, but before the ring is secured on the hub, twelvt^ 



HOME MECHANICS FOll AMATEUKS 273 

equidistaut holes are drilled transversely through the 
hub, near its center, and in each hole is inserted a piece 
of No. 12 copper wire one-half an inch long. The ends 
of the pieces of copper wire are allowed to project one- 




FiG. 243 A. Perspective View of Small Gramme Ring Motor. 

sixteenth of an inch beyond the sides of the hub. The 
ring is placed on the hub, and the ends of the wire pro- 
jecting from adjacent coils, h, are twisted together and 
attached by means of solder to the copper wire pins 



274 HOME MECHAXICS FOR AMATEURS 

extending through the hub and forming the commu- 
tator bars, the covering being removed from the ex- 
tremities of the Avire. It will thus be seen that to each 
commutator bar is connected the beginning of one coil 
and the end of the adjacent coil, so that by means of 




Fig. 244. Sectional Side Elevation of a Small Motor, 



these connections the winding of the armature becomes 
continuous. 

The posts in wliich the armature shaft is journaled 
are perforated near tlieir upper ends Avith a hole of a 
size adapted to receive the armature shaft, and these 
holes are counterbored from the inner surfaces of the 
posts, and a wire of the same diameter as the shaft 



HOME MECHANICS FOR AMATEUES 



275 



is placed in the position of the armature shaft, and 
Babbitt metal or type metal is poured into the open- 
ings around the shaft, forming the journal boxes. A 
hole is bored in the top of each post before casting the 
metal, to form an anchorage for the journal box, and 
after the casting, the anchorage is drilled through to 




Fig. 245. Front Elevation of Small Motor. 



the opening of the journal box to form an oil hole for 
the armature shaft. 

The journal box on the side of the commutator is 
made to project beyond the inner face of the post to 
receive the disk, f, which carries the commutator 
springs, r/. This projection is made by clamping to the 
post a piece of wood having in it a hole corresponding 



276 HOME MECHANICS FOE AMATEURS 

Avitli that ill the post. After the journal box is cast, 
the extra piece of Avood is removed, leaving a sleeve 
upon which to place the disk, /. This disk is an inch 
and a half in diameter and ti of an inch thick. 




Fig. 246. Armature of Small Motor in Process of Construction. 

To the inner face of the disk, /, are clamped the com- 
mutator springs, g, by means of small blocks, as shown 
in the perspective view, these blocks being held in place 
by screws passing through the disk into threaded holes 




Fig. 247. Apparatus for Winding Armature Coils. 

ill the bh)cks. The commutator springs are curved 
outwardly and their ends are turned backward to- 
ward the disk, /, and their extremities rest upon the 
commutator bars, as shown in Figs. 243 and 244. 



HOME MECHAXICS FOT^ AMATEUES 



277 



Tht' disk, /, and the chimpiuo blocks are made of 
vulcanized fiber, which is strong and at the same time 
a i'ood insulator. The commutator springs, g, are 
nmde of hard rolled copper, and their inner ends are 
adjusted so as to touch diametrically opposite commu- 
tator bars. The best adjustuunit for the commutator 
sprino-s is found by moving the disk, f , in one direction 
or the other. It will be found that the maximum ef- 
fect is secured when the contact surfaces of the com- 
mutator springs are nearly in a vertical line. 

The disk, f, is clamped in any desired position by an 
ordinary wood screw, li, which passes loosely through 
the post and is screwed into a wooden thumb nut bear- 
ing against the outer surface of the post. The ter- 
mi'iials of the field magnet. A, are connected directly 
with the binding post and also with the outer ends of 
the commutator springs, (j. as shown in Figs. 243 and 

245. 

With one cell of dry battery the motor makes about 
1,800 revolutions per minute, but it does not develop 
its maximum power until one or two cells are added in 
parallel. Any of the dry batteries will run it for short 
periods, but if it is required to run it continuously for 
any length of time, one or two cells of Bunsen or a 
Fuller battery should be used. 

The motor being shunt wound, is practically self- 
regulating. Its speed with any amount of battery 
power does not much exceed 2,000 revolutions per 
minute. 



278 



HOME MECHAXICS FOE AMATEURS 



HOW TO MAKE A SEWING MACHINE MOTOR 
WITHOUT CASTINGS* 

The accompanying drawings, together with the fol- 
lowing instructions, will enable any mechanic of aver- 
age ability to build a highly efficient motor that will 
operate the heaviest of family sewing machines with a 




Fig. 248. Sewing Machine Motor Made by an Amateur. 

consumption of electrical energy only a trifle greater 
than that required to maintain an incandescent lamp. 
All the materials entering into the construction of the 
motor may be procured in almost any town or small 

* By Cecil P. Poole. 



HOME MECHAXICS FOR AMATEURS 



279 



city, and tlie total cost of tlic macliiiic, cxccptiiii»-, of 
course, the la])or, slioiild not exceed five dollars. 

The first operation is that of niakin.1!: th(^ magnet, 
which consists of a bar of ordinary wron<»ht iron, 1^ 
inches square and 19 inches lon^^-, bent (while red hot) 
into a U, as shown by Fi"'. 248. After bendin.u^ the iron 
into shape, cut out two concavities in the limbs, as indi- 
cated by the dotted lines, to a circle of 4| inches diam- 



-^~ -. 



Q 



Fig. 249. Field Magnet. 



Fig. 250. 

Field Magnet Ready for 
Armature. 



eter. The center of the circle of which the concave sur- 
faces form arcs must be 5^ inches from the short part 
of the U, known as the mai^net yoke, and exactly mid- 
way between the magnet limbs, so that an equal amount 
will be cut out of each limb. This cutting can be done 
by any blacksmith, as it does not need to be precise in 
the matter of the surfaces of the concavities, the only 
object being to remove the bulk of metal that is to be 
cut away in order to form the armature chamber. 

Next smooth up the sides of the magnet on the fiat of 
an emery wheel, rounding off the corners so that a face 



280 HOME MECHAXICS FOR AMATEUES 

view of the ends of the limbs will be as shown in Fig. 
254 ; the faces, f, f, should also be smoothed off with the 
emery wheel, as these form the base of the machine. 
Then bolt the magnet to tlie face-plate of the lathe so 
that the center of the circle, a, to which the magnet 
limbs were cut away coincides with the lathe centers, 
and bore out the armature chandler to 4^ inches in 
diameter, leaving the magnet as shown by Fig. 250 ; 
the curved surfaces forming the armature chamber are 
known as pole-faces. If the sides of the magnet (by 
"sides" are meant the part facing the reader in Figs. 
248, 250, and 253, and the corresponding part on the 
other side of the magnet) were not ground to a true 
parallel on the emery wheel, and asit is highly probable 
that they were not, it is advisable to take a slight cut 
over the whole side exposed while the magnet is on the 
face-plate so as to have it perfectlj^ plane, and also take 
a cut over the opposite side to insure parallelism. 

The journal yokes and boxes come next. There will 
be two bearings and yokes, one for each side of the 
machine. Fig. 251 shows the parts necessary for one 
yoke and bearing ; //, y are brass strips 6f inches long, 
1 inch wide, and A inch thick, with rounded ends; h 
is the box, made of a piece of round brass rod 1 inch 
in diameter and 2 inches long over all, one end being 
turned down to f inch diameter for a distance of f 
inch, a f-inch hole being drilled through the center 
and a ^-inch hole being drilled in one side far enough 
to let the point of the drill through into the bore of 
the box; c is the oil reservoir, consisting of a piece of 
brass tubing 1 inch long, f inch in diameter outside 
and f inch diameter inside, with one end permanently 
stopped by a plug soldered in and the other end 



HOME MECIIAXICS FOI] A:\IATKrES 



281 



threaded for a distance of tV incli. The hole iii the 
side of the box, h, is threaded to match the thread on 
the end of the tube, c, which is packed with lamp 
wick, filled with oil, and screwed in the box when the 
machine is completed and ready to run. The yoke 
strips, 7/, 7/, haye each a ^-ii^t'b ^i<>l^' diilbnl exactly in 
the center, seyeral nicks being* filed in the edges of 
these holes. Before putting the yoke together, tin the 
edges of these central holes and tin the small end of 



y y 



O 



o 



Fig. 251 



Fig. 252. 
Parts of Yoke. 




Fig. 253. 

Placing Yokes in 
Position. 




Fig. 254. 
Magnet with Yokes. 



the box, h; then mount the st 
box so they will be at right ang 
so that the hole in the side of 
two of the legs formed by the 
whole at the center. Be sure 
edges of the holes with solder. 

When both yokes haye been 
block of wood 1^ inches thick to 
chamber in the magnet limbs 



rips on the end of the 
les with each other and 
the box comes between 
strips, and solder the 
to fill the nicks in the 

assembled, turn up a 
fit closely the armature 
without spreading the 



282 HOME MECHAXICS FOE AMATEURS 

latter. This Mock sliould liavc a JJ-iiu-li linlc in the cen- 
ter, and it will be better to drill the hole first, mount 
the block on a f-inch mandrel and turn it up true with 
the central hole. Put this block in the armature cham- 
ber with its f-inch mandrel in the central hole, thread 
one yoke on one end of the mandrel and the other on the 
other end, turning the legs of each yoke to the position 
shown by Fig. 253. Clamp the Avhole together securely 
and drill four |-inch holes, h, h, h, h, through the mag- 
net limbs and both yokes ; punch-mark one yoke and the 
face of the magnet limb on Avhich it rests so that in 
reassembling the machine the various parts will come 
back to the original position in Avhich they Avere drilled ; 
then take off the clamps and take off the yokes, remove 
the yokes and wooden block and anneal the magnet by 
heatina* it to a bright red and allowing the fire to die 
out with the iron covered up in the coals. 

For mounting the yokes permanently on the magnet, 
four steel machine screws and eight distance pieces 
will be required. The screws are \ inch in diameter 
and 6| inches long under the head, and the head 
should be slotted. The distance pieces to hold the 
yokes away from the magnet are made from round 
brass rod 1 inch in diameter ; two of them are 1 A inches 
long, two are If inches long, two are 2x1 inches long, 
and the remaining two are 2;^ inches long. Fig. 254 
shows one yoke mounted, with its distance pieces, z, z, 
z, z, and .s, .s, i<, s, represent the thread ends of the 
screws. The yokes should be carefully fitted or trouble 
may result from non-alignment of the bearings. 

The armature structure comes next From some 
dealer in armature stampings procure one hundred 
rings of charcoal iron 4 inches in diameter outside and 



HOME MECHAXTCS FOE AMATEURS 



283 



3 inches in (liiuneler inside. These rin<j;s must not be 
over iV ineli thick and preferably abont q\ inch thick. 
Not all of the one hnndred will be needled, bnt many 
will be spoiled in drilling. From a dealer in electrical 
snpplies procnre two rings of vnlcanized fiber, the 
same diameter ontside and inside as the iron rings, and 
I inch thick. On the face of one ring space off twelve 
eqnidistant points on a circle scribed around the cen- 
ter of the ring's face midway between edges, as shown 
by Fig. 255, in which the points are indicated by 




Fig. 255. 

Laying Out the 
Armature. 




Fig. 256. 
Brass Disks. 




Fig. 257. 

Position of Holes 
for Bolts. 



Fig. 258. A Trapezoid. 



Fig. 259. Tie Rod. 



c, c, g, e, c, (/, c, c, g, c, c, g, those marked g being 90 de- 
grees apart. Take two brass disks 4 inches in diam- 
eter I inch thick, with a ^-inch boss 1 J inches in diam- 
eter on one side, as shown by Fig. 256, which may be 
obtained from any model making establishment, and 
drill through the center a J-inch hole, indicated by 
dotted line in the sketch. Clamp on the smooth side 
of one of these disks the fiber ring that has been scribed, 
letting the marked face come uppermost, and drill 
four ^-inch holes at the points marked g, r/, g, g, on the 



^84 HOME MECHANICS FOE AMATEURS 

face of the ring, through both the ring and the brass 
disk. Next mount on a f-iueh mandrel a bhick of 
wood 2^ inches thick and hirge enough to permit turn- 
ing it down to a roller 3 inches in diameter; iustead of 
turning it to measurement, however, uuike it fit snugly 
into the interior of the iron and fibre rings. When this 
block is turned to size, thread on one end of the mandrel 
tlie brass disk that has only a central hole, next put the 
unnuirked fiber disk on the wooden block, doAvn to the 
brass disk, and follow with the iron rings, i:>utting on 
last the fiber ring that has been drilled and then thread- 
ing on the mandrel the brass disk that was also drilled 
with the fiber disk. Turn the disk so that the holes 
near its edge agree with those in the fiber ring under 
it and compress the whole arrangement with clamps. 
If there are so many iron disks that the fiber ring 
cannot be drawn down oyer the end of the wooden cen- 
tering block, take off enough to let this be done, as it 
is imperatiye that all the rings and disks should be 
accurately centered with each other. Then drill ^-incli 
holes through the whole mass, entering the drill in the 
holes already bored in the top brass disk and fiber ring. 
These four ^-inch holes are for tie-bolts to hold the 
armature core together. 

When the drilling is finished, punch-mark each brass 
disk and fiber ring near one of the :^-inch holes (the 
same one in each case, of course), remove the clamps 
and the brass and fiber loieces, run a wire through the 
hole in the iron rings corresponding to the one marked 
on the fibers and disks and tie them loosely together 
until time to assemble the core. Then clamp the two 
fiber rings together, with the marked holes in align- 
ment, and drill through both rings a tV inch hole at 



HOME MECHANICS FOE AMATEURS 285 

each point marked e^ leaving each ring as shown by 
Fig. 257. 

Next cut out of hard wood twenty-four trapezoidal 
blocks (Fig. 258) f inch thick, f inch wide at one end, 
-J inch wide at the other, and ^ inch long. In the 
center of sixteen of these drill a iV iuch hole; in the 
center of the other eight drill a j-inch hole. Pin the 
sixteen trapezoids having small holes to the faces of 
the two fiber rings, putting the pins through from the 
back through the tV inch holes in the rings; the pins, 
which must be of brass, should be a tight driving fit so 
that the trapezoids will not tend to slip off, and the 
faces of the latter should be coated with shellac varnish 
to prevent their turning on the pins. 

The tie-bolts, mentioned above, are of brass, fV inch 
in diameter and 3f inches long, threaded at each end 
for a distance of re inch. They must be insulated where 
they pass through the core by wrapping paper on 
them, gluing each layer and putting on enough to 
make the insulated portion fit snugly in the ^-inch holes 
drilled through the rings. Cut a strip of manila paper 
2^ inches wide and wrap it tightly on the bolt, leaving 
an equal length of uncovered metal at each end. When 
the right thickness of insulation is obtained, drill two 
tV inch holes in the bolt, exactly 2t6 inches from center 
to center, and equal distances from each end (this dis- 
tance, if the bolt has been accurately cut to the length 
specified, will, of course, be || inch). Two nuts must 
be also provided for each bolt, and two steel pins which 
are driving fits in thexV inch holes,and slightly tapered. 
One of these tie-rods, without its nuts and pins, is 
shown by Fig. 259. 

Then assemble the armature core on its woodeji cen- 



286 



HOME MECHANICS FOR AMATEURS 



tering block, using enough iron disks to make the iron 
part measure 1| inches in thickness when compressed 
and being careful to ha^e those of the J-inch holes that 
were marked on the fibre pieces come in line with the 
hole through which the wire holding the iron disks 
together was run. Leave off the brass disks for the 
present. Through each ^-inch hole put a tie-rod, clamp- 
ing the structure until the steel pins can be put in the 
holes in the tie-rods; enough iron disks should be put 
in to prevent any looseness when the clamps are re- 
moved. Fig. 260 shows the complete structure. After 






Fig. 260. 

Armature Ready for 
Winding. 



Fig. 261. Fig. 262. 

The Slitted Tube for Commutator. 



the tie-rods are pinned in place the remaining trape- 
zoids are put on over the ends of the rods; a little 
groove will have to be cut in the back of the trapezoid 
to accommodate the steel pin in the end of the tie-rod. 
The commutator comes next, and while it Avould be 
advisable to buy a complete commutator, a very serv- 
iceable one can be made with proper care in following 
out the instructions given. If the l)ui]der prefers to 
buy the commutator, tlie dimensions accompanying the 
order must l)e tlu^se : Diameter of brush surface, 1 
inch; length along the shaft, li inches; number of 



HOME MECHAXICS FOR AMATEURS 287 

segments, 12. If the commutator is to be built along 
with the rest of the machine, proceed as follows : 

Take a piece of brass tubing, 1 inch in diameter out- 
side, Avitli a wall about I inch thick, and measuring 
2^ inches long. Slit it at twelve equidistant jwints 
for a distance of 1| inches from one end, as shown by 
Fig. 261, and insert the unslitted portion in a hole in a 
block of wood that just fits the tubing; the block 
should be 1 inch thick and nailed to a bench or other 
support. Then bend outwardly the narrow strips made 
by slitting the tubing until it looks like Fig. 263; the 
wings should be brought to a right angle with the body 
of the tubing not slitted, and hammered out flat. 
Number the ^Svings" by means of punch marks, from 
one up to twelve, and then carry the slits along the 
length of the uncut portion of the tube, cutting it up 
into twelve pieces like Fig. 264. Next turn up two 
rings of vulcanized fiber 2 inches in diameter outside, 
1 inch in diameter inside and } inch thick, and fit 
around the circumference of each twelve steel screws, 
^ inch in diameter and f inch long over all, without 
heads, as shown bv Fig. 265,. the screw-holes being car- 
ried clear through so that the point of the screw may 
emerge on the inside of the ring. Tut thirty-six strips 
of oil paper (the kind used Avith copying books to pro- 
tect the leaves from moisture) ^V in<'li thick, | inch 
wide, and H inches long. Assemble the pieces of the 
commutator in numerical order within the two fiber 
rings, one ring at tlie wing end and one at the other 
end of the tubular part, put three slips of oil paper be- 
tween each x^air of neighboring pieces of tube, and 
draw the segments toward the center by means of the 
little screws until the oil paper slips are clamped so 



288 



HOME MECHANICS FOH AMATEURS 



tightly between the brass segments that they cannot be 
pnlled ont with the fingers. In order to have the com- 
mutator come together and form an api)roximately 
true circle, a saw blade sV inch thick should be used in 
cutting the segments out of the tube. Then by judi- 





FiG. 264. One Segment. 



Fig. 263. 

Commutator Tube Before it is 

Cut into Segments. 





Fig. 265. 
Fiber Ring with Screws. 



Fig. 266. 
The Commutator. 



cious setting up on the screws the surface can be 
brought sufficiently near to a true circle as to require 
no truing up in the lathe. The protruding edges of 
the oil-paper slips can be cut off even with the brass 
with a sharp knife. 

The core of the commutator may be made of wood; 



HOME MECHANICS FOR AMATEURS 289 

mount a block ou a f-incli mandrel and turn it up to 
the exact diameter of the interior of the commutator ; 
then taper it slightly so that it will pass through the 
commutator before binding, and drive it home as tight 
as possible without straining the fiber rings that hold 
the segments. Cut off the block ^ inch beyond the 
wing end of the commutator and flush Avith the other 
end. The complete commutator is shown by Fig. 266. 

The next piece of machine work is the shaft, shown 
by Fig. 267. It is turned up from a piece of |-inch bar 
steel 10 J inches long. The dimensions are as follows : 
A^ f inch diameter, 2tV inch long; B^ f inch di- 
ameter, 1^ inches long; C^ J inch diameter, 3'^ inches 
long; Z), f inch diameter, 3 A inches long. Last in the 
list of machine work on the motor proper are the brush 
holders, one of which is shown by Fig. 268, the drawing 
showing two views. The holder is a piece of brass 
tubing, ^ inch internal diameter and 1| inches long', 
mounted on a piece of strip brass f inch wide and A 
inch thick, the other end of which is bent into a loop, 
as shown, and provided with an insulating bushing, t^ 
of T6 inch fiber. The internal diameter of the bushing- 
is a trifle over an inch when the clamping screw is 
loose, and the diameter of the loop in the brass strip is, 
therefore, 1^ inch maximum. This loop is intended to 
fit around one of the distance pieces, z, Fig. 254, from 
which it is insulated by the bushing, t. 

The brush is a piece of round carbon, ^ inch in di- 
ameter and 1 inch long; it should fit snugly within the 
tube forming the holder, and a spiral spring, f inch 
in diameter, made of No. 16 brass wire, must be pro- 
vided to force the brush outwardly on to the com- 
mutator. One brush holder is attached to the lower 



290 HOME MECHAISTICS FOR AMATEURS 

left-hand distance-piece, c^, and the other to the upper 
right-hand piece, the tubular part of the holder set- 
ting verticalh^, between the magnet poles, with its in- 
ner end not more than i inch from the surface of the 
commutator. Electrical connection is made Avith the 
brush arm by means of a piece of flexible cord, such 
as is used in hanging incandescent lamps, one end of 
the cord being soldered to a copper Avasher, which is 
clamped under the head of the screw on the brush arm. 
This cord is known as No. 18 cotton-covered lamp- 
cord, and may be procured from any dealer. It should 
be untwisted and one length used on each brush holder ; 
the cord need not be more than 6 inches long. 

We are now ready to wind the magnet and armature 
cores. The armature core must first be covered all 
around the outside surface with muslin; cut a strip 2 
inches Avide and 25 inches long and, after varnishing 
the periphery of the core with shellac, wind on this 
muslin strip, being sure that it is tightly wound. If it 
is pulled tight, it will make two layers; Avhen the 
strip has been carried once around, varnish the surface 
of what is on the core, and then wind on the other 
layer of muslin. Then varnish the Avhole outside sur- 
face. Cut out 24 strips of oil paper, each lye" inches 
wide and 2 inches long, and bend up the edges, making 
the crease ^ inch from each edge, so as to form shall oav 
troughs the Avidth of AAiiich will be the same as the 
space betAveen the trapezoids on the end of the core; 
apply two of the troughs to the inside and outside 
circles of the core, as shoAvn in Fig. 270, and tie them in 
place with No. 40 or No. 50 scAAing cotton, one strand 
at each side of the trough. Then wind on an old cot- 
ton-spool 68 feet of No. 26 double cotton-covered mag- 



HOME MECHANICS FOR AMATEUES 



291 



net Avirc, hook the outer end around one trapezoid, as 
in Fig. 271, and Avind into the wiring space between 
this trapezoid and its right-hand neighbor a coil the 
full width of the space, which should take 26 turns in 



A 


B 


I — 





Fig. 267. The Shaft. 

width, putting five layers in, or 130 turns, to each coil. 
When the first coil is done twist to the final end the 
beginning end of the wire which is to wind the next 
coil, and proceed with that one in the same way. Care 
must be observed to put exactly the same number of 
turns in each coil and to twist the ending of each coil 
to the beginning of its neighbor on the right. When 
the armature is wound, put on the brass disks that 
were left off when the core was assembled, threading 
the tie-rods through the holes near the edoes of the 




Figs. 268 and 269. 
Brush Holders. 




Fig. 270. 

Section Prepared for 
Winding. 



Fig. 271. 

Beginning the 
Winding. 



disks, and putting the boss on each disk outside; clamp 
the disks hard against the wooden trapezoids by means 
of nuts on the tie-rods. The holes in the disks must 
be bushed with little pieces of fiber tubing and a fiber 



g92 HOME MECHANICS FOE AMATEUES 

washer must go under each nut, in order to insulate 
the tie-rods from the disks; otherwise the armature 
would run destructively hot. 

Insert the shaft in the center of the structure, letting 
that part marked B in Fig. 267 come on the side where 
the ends of the armature winding are, and pin the 
brass disks to the shaft through the bosses. The com- 
mutator goes on the part of the shaft just referred to, 
and it should be a driving fit, so as to obviate pinning 
or keying it to the shaft. Then connect up the ends 
of the armature coils to the lugs of the commutator, 
leading each end straight out, parallel with the shaft, 
to the nearest lug. If the ends were twisted together 
in accordance with the directions, the result will be 
as shown diagrammatically by Fig. 272. 

Prepare for winding the magnet coils by making a 
winding bobbin as follows : On a piece of board an 
inch thick and 4 inches square lay out a square meas- 
uring If inches on a side, the scribed square being 
symmetrical with the edges of the board; clamp an- 
other similar piece of board to the one marked, and at 
the corners of the scribed square drill |-inch holes 
through both boards; in the center of the square drill 
a ^-inch hole. Then make a mandrel of ^-inch round 
iron, the central part being full diameter and 2J 
inches long, and the ends being turned down to pass 
through the central hole in the board. Mount the 
boards on the ends of the mandrel and run |-inch iron 
rods through the corner holes, forming a sort of reel, 
as shown by Fig. 273. Jam the boards against the 
shoulders of the mandrel by means of lathe dogs on 
the outer ends of the latter, and drive a nail in the 
face of each board so that the dog will drive the board 



HOME MECHANICS FOR AMATEURS 293 

without slip. The dogs must be so adjusted, of course, 
as to drive both boards iu their proper augular posi- 
tions, maintaining the parallelism between the ^-inch 
rods and the mandrel that is necessary to form a per- 
fect coil. 

Mount this winding frame in the lathe and wind a 
coil on it of No. 21 double cotton-covered magnet wire, 
putting as many turns as possible (it should take sixt}^- 
six) between the faces of the wooden blocks and mak- 
ing the coil twenty-seven layers deep. The starting- 
end may be secured to the projecting end of one of the 
|-inch rods to give the necessary tension to the first 





Fig. 272. Fig. 273. 

The Winding. Reel for Winding Field 

Magnet Coils. 

layer of wire, and at least a foot of the starting end 
should be left free. When the coil is finished, tie it at 
each of the four corners with strong linen thread, 
bending the final end sharply backward over one of 
these corner threads to keep the top layer snug; take 
the winding frame apart and varnish the coil all over 
with shellac, setting it aside to dry while the second 
coil is wound. This is exactly like the one already 
wound. 

Then take the journal yokes and their bolts and 
distance pieces off the magnet and wrap the magnet 
limbs with muslin from ^ inch above the bolt holes 
up to the bend, putting two layers on each limb and 



294 HOME MECHANICS FOE AMATEURS 

varnishing it on the outside of each layer. When this 
is dry, turn the magnet upside down, thread on each 
limb a fiber washer 3f inches square and i inch thick, 
the hole in the Avasher fitting the magnet limb snugly ; 
varnish the faces of the washers now uppermost and 
slip the coils on the limbs down on the washers while 
the varnish is wet, so that the latter will stick to the 
coils. In putting on the coils, see that the beginning 
end of each coil goes on first, so that when the machine 
is set right side up the final end of each coil will be 
nearest the armature. Follow each coil Avith another 
fiber w^asher like those first put on the magnet, and 
then reassemble the journal yokes and distance pieces 
on the magnet, this time putting in the armature as you 
go along and also putting on the brush holders and 
brushes. The holders should be so adjusted that the 
ends of the brush tubes are tV to ^ inch away from the 
surface of the commutator. 

The free ends of the magnet coils nearest the arma- 
ture are connected to the brushes by means of flexible 
lamp cord, as described in the instructions for making 
the brush holders, the end of the flexible cord being 
soldered to the end of the magnet wire close up to the 
coil. Th upper ends of the magnet coils go to the ter- 
minal block, which is a block of wood, 1 J inches square 
and 4 inches long, bolted on the top of the magnet 
yoke, and carrying two binding posts, which form the 
terminals of the machine. The motor is bolted to the 
table of the sewing machine, with one leg right on the 
edge of the table and in such position that the pulley 
of the motor, which must go on the end of the shaft 
away from the commutator, is in line with the belt 
pulley of the machine. The motor pulley should be 



HOME MECHANICS FOR AMATEUES 



295 



one-half the diameter of the pulley on the sewing ma- 
chine, and be of the same width and depth of groove. 

The regulator is shown by Figs. 274 and 275, the 
former being the front view and the latter the back. 
Referring to Fig. 274, A is a wooden arm, 9^ inches 
long, I inch thick, and tapering from ^ inch to 1^ inches 
in width. The narrow end is faced with a thin strip of 
copper to make contact with the buttons, c^ which are 
simple brass bolts with flat heads; the wide end of the 
wooden arm is split to straddle the shaft, to which it is 
pinned as well as clamped. L is the lever controlling 




Fig. 274. 
Regulator — Front View. 



Fig. 275. 
Regulator — Back View. 



the arm, .4; it is made of |-inch round iron rod, bent 
to form a right angle; the lever portion is 6 inches 
long; the length of the horizontal portion on which 
the lever. A, is mounted is the same as the width of 
the sewing machine table on which the motor is to be 
used. The back end of the shaft is journaled in the 
base board, C,, and the front part in a wooden bearing, 
B, which is bolted to the under side of the sewing ma- 
chine table between the narrow drawer and the pan. 
The baseboard, C^ is 6 inches wide (vertically) and 40J 
inches long. It is fastened to the under side of the ma- 
chine table, flush with the back edge. The lever, L, is 
to be moved by the right knee of the machine operator. 



296 HOME MECHANICS FOE AMATEURS 

The arm, A^ is normany held in its highest position 
bv the coil spring shown, in which position the current 
is cut oft the motor entirel}^ The contact buttons, Cy 
are -J inch in diameter; the bolts of which they are 
the heads are A inch in diameter and long enough to 
protrude | inch on the reverse side of the base board. 
This side is shown by Fig. 275. The resistance coils 
consist of German silver wire, No. 20 B. and S. gauge, 
wound into coils on a f-incli rod (the rod being re- 
moved, of course, Avhen the coil is formed). The piece 
of wire forming the upper coil should be 100 feet long; 
the next coils contain 90, 80, 70, 60 and 50 feet of wire, 
respectively, in the order named. The binding posts, 
Tt and Toy are connected as shown, the connection be- 
tween Ti and the iron shaft being made by means of 
flexible cord which will follow the movements of the 
shaft. On the front the shaft is connected to the cop- 
per facing at the small end of the arm. A, by means of 
No. 16 copper Avire. All the connections on the back 
are made with No. 16 copper wire, preferably but not 
necessarily insulated. 

The back surface of the base board must be covered 
with a sheet of asbestos over a thin sheet of fiber. The 
ends of the resistance coils are twisted together and 
soldered, and the connecting wires should be soldered 
on at the same time. The coils are held on ordinary 
porcelain knobs, fastened to the board by Avood screAvs. 
The connecting wires should be bent into loops AA^here 
they connect Avith the bolts, c^ and a copper Avasher 
should go under each nut and on top of the loop of the 
connecting Avire. 

The connections betAveen the motor and the regulator 
and the source of current supply are as folloAvs : From 



HOME MECHA^TICS FOR AMATEURS 297 

T^ to one binding post on the motor, from T. to one side 
of the supply circuit, and from the other binding post 
on the motor to the other side of the supply circuit. 

The motor above described will run satisfactorily on 
any direct-current incandescent lamp-circuit of 100 to 
120 volts pressure. If it is desired to build the ma- 
chine for use in connection with a battery, the windings 
will have to be changed as follows : Armature coils. 
No. 13 wire, 8 turns wide and 1 deep, each coil; field 
magnet coils. No. 8 wire, 5 layers deep, 18 turns per 
layer, each coil ; regular. No. 13 wire, the coils having 
one-tenth the number of feet specified above. 

The battery to run such a motor must give 8 volts 
and from 10 to 20 amperes, according to the load on the 
motor ; consequently four cells will be required. 

Should the reader desire to build a standard shunt- 
wound motor of i horse power instead of the series- 
wound type specified, the same frame may be used, 
the onlv variation beino^ in the manner of windins:. 
In order to wind the machine as a i horse power mo- 
tor, to work on a 110 volt circuit, the armature coils 
must consist of No. 27 wire, double cotton-covered, 
each coil being 9 layers deep and 28 turns in width — 
252 turns, total, per coil. The magnet coils will con- 
sist of No. 25 wire wound to a depth of 39 layers, with 
as many turns lengthwise as can be got in the space of 
2^ inches allotted for the coil length; with careful 
winding, 92 turns can be put in each layer, giving each 
magnet coil a total of 3,588 turns. 

In order to change the design into a \ horse power 
motor, the magnet must be made of iron 2^ inches 
square, instead of IJ inches, and the armature, shaft, 
journal-yoke bolts, etc., must be made exactly 1 inch 



2^8 HOME MECHANICS FOE AMATEURS 

longer, axiallj, than the above measurements specify. 
The windings will be No. 24 wire on the armature, each 
coil 5 layers deep and 21 turns wide ; No. 22 wire on the 
magnet, each coil being 37 layers deep and 74 turns 
long (or as many as the 2^ inch space will take). 
The number of armature coils and all other data not 
specified in this paragraph Avill remain precisely as in 
the original instructions above. 



A DESIGN FOR AN ELECTRIC LAUNCH MOTOR 

For the propulsion of an electric launch a motor 
must unite elements of efficiency, compactness, and 
strength to a degree scarcely necessary in any other 
situation. The design given here is for a motor of un- 
usual simplicity of construction, which can easily be 
built by an amateur at small cost. It is intended for 
a boat of about 24 feet over all and 4 feet 6 inches 
beam, drawing 18 inches, and is capable of propelling 
such a craft at a speed of 7 miles per hour. Gearing of 
all sorts has been dispensed Avith, the motor being 
adapted for direct attachment to the propeller shaft. 
While the description below refers primarily to a motor 
for a craft of tliis size, dimensions are also given for 
the construction of motors for smaller launches. 

Without going into the details of calculation, it may 
be stated that for such a boat the most efficient service 
will be had from a four-bladed screw, about 14 inches 
in diameter, 12 inches pitch, 35 per cent, blade area 
(by which is meant with blades having a total project- 
ed area equal to 35 per cent, of that of a 14-inch disk). 



HOME MECHANICS FOR AMATEURS 299 






ui 



S3 

'So 

d 
o 



300 HOME MECHANICS FOE AMATEUES 

rimuing' at 880 revolutions per minute. Such a screw 
will absorb about 4 horse power. No very definite fig- 
ures of speeds and powers can be given, as these de- 
pend very largely upon the shape of the boat, its full- 
ness fore and aft, the moulding of the runs, etc. The 
motor described below will give a speed of 7 miles per 
hour to a rather full-modeled boat of the size indicated, 
when fully loaded to a displacement of 5,000 pounds. 
This means, assuming that the boat itself weighs about 
1,000 pounds, a carrying capacity for about ten or 
twelve passengers. 

The storage battery consists of 24 elements, arranged 
in two series of 12 cells each, each cell being of about 
80 pounds weight. These cells contains 13 plates each, 
about 7f inches square, and are about 7^x8^ inches 
square by 11 inches in height, these measurements be- 
ing outside of the rubber containing jars. They should 
be mounted in two Avooden boxes, about 8^ inches 
wide by 11 inches deep inside and about 7 feet 6 inches 
long. These make convenient seats in the boat, and 
their lids may be covered with cushions. They should 
be placed side by side amidships, as low as possible 
and a little forward of the center of gravity of the boat 
to compensate for the weight of the motor, which is 
installed well aft. Such cells may be bought from 
any one of several well-known American makers of 
accumulators. Elements in glass jars should not be 
used, on account of the danger of breakage. 

For the smaller sizes of motor described below, or, in 
other words, for smaller boats of the same general 
type, the number of cells remains the same, but their 
size may be proportionately reduced. With cells of 
the same type, having plates of the size given, a 3 horse 



HOME MECHANICS FOR AMATEURS 301 

])()\\ er boat will require those having 9 plates and a 2 
horse power boat those having 7 plates. 

Terminals for charging should be attached to the 
boxes containing the cells. It is by all odds the best 
plan to charge the cells in the boat, and not to at- 
tempt to remove them for this purpose. 

The capacity of these outfits on one charge is about 
3 hours' run at full speed, or about 7 hours' run at 
about 4^ miles per hour, thus giving the boat in each 
case a cruising radius of about 30 miles. If a larger 





Figs. 277 and 278. Section of Coupling. 

cruising radius is desired, it may be attained by the 
use of larger cells, but, as these are heavier, their use 
means a corresponding decrease in the passenger carry- 
ing capacity of the boat. 

The motor illustrated herewith is of a four-pole in- 
closed type, waterproof and intended to be attached 
directly to the screw shaft. Some form of flexible 
coupling is recommended, that shown in Figs. 277 and 
278 being very simple and easily made. It consists of 
two cast iron flanges, the larger about 12 inches in dia- 
meter for the motor to be described and proportion- 



302 HOME MECHANICS FOE AMATEUES 

ately smaller for the smaller motors. These flanges are 
mounted, one on the motor shaft and the other on the 
propeller shaft, so that the smaller runs inside the 
larger, with a clearance of about 1 inch all round. 

In the cylindrical surfaces of each are cut eight win- 
dows, the edges of which are rounded off as shown in 
Fig. 278. Through these windows a piece of cotton 
belting, 1 inch wide, is laced as indicated in the figure, 
its ends being cemented together. The whole forms an 
inexpensive and satisfactory coupling, which will 
largely prevent any strain of the shaft due to the flex- 
ure of the boat under loads in a seaway. 

A thrust bearing, to take up the forward thrust of 
the screw shaft, is also necessary. A simple and satis- 
factory type is illustrated in Figs. 279, 280 and 281. 
Upon the screw shaft are mounted four steel collars, 
each about three times the diameter of the shaft and 
about 1 inch thick. These are provided with set 
screws. A cast iron box contains the brasses against 
which these collars Avork. This box, it must be re- 
membered, receives the whole forward thrust of the 
screw, and must not only be made strong enough to re- 
sist this, but also arranged to communicate the pres- 
sure to the frame of the boat. A good plan for mount- 
ing it is to place in the bottom of the boat a stout tim- 
ber, long enough to l)e screwed to several of the after 
frames, and arrange the thrust bearing with lugs for 
four or six lag screws so that it may be securely at- 
tached to this. In the size of boat described above, at 
full speed, the forward push of the screw will be about 
220 pounds, but in a sea, or if there is any obstruction 
in the way, this may be easily doubled. 

The box frame of the thrust block, as the illustra- 



HOME MECHANICS FOR AMATEUES 



303 



tions very clearlj^ show, is grooved to receive three 
horseshoe shaped brasses, each about au inch thick. 
These straddle the shaft between the collars, Avhich are 
adjusted to bear equally on the brasses. The box is filled 
with oil to a level so that the collars run in it, con- 
stantly lubricating the bearing surfaces of the collars 




J^ 



M 




w 




Figs. 279, 280, 281. 
Elevation, Plan, and Cross Section of Thrust Bearing. 

and brasses. If one of the brasses heats, it may be 
lifted out and turned around or replaced with another 
without stopping the boat. A light hinged cover com- 
pletes the thrust block. For the smaller sizes of motors 
indicated three collars on the shaft and two brasses 
will be sufficient. 

The shell of the motor, Figs. 282 and 283 is a cylin- 



304 HOME MECHAXICS FOR AMATEURS 

(Irical iron casting carrying the four polar projections, 
A. It is shown in the drawings with a perfectly plain 
exterior, but it should be provided Avith feet. These 
are not shown in the drawing, as they should be made 
to fit the shape of the hull. 

At each end of the heavy field ring is a cylindrical 
projection, Cy stiffened with four columnar ribs, R^ to 
receive the cap screws which fasten on the end plate. 
The field casting may be finished on the lathe in two 
operations. It should be chucked and the field bored 
out to a diameter of exactly Gre inches. Upon the ac- 
curate boring of the field and turning of the armature, 
or, in other words, upon keeping the air spaces as small 
as possible, will depend much of the satisfactory per- 
formance of the motor. 

The end surfaces for the reception of the end plates 
are trued off at the same time the field is bored, and 
the seat, aS*^ for the brush holder ring, B^ is also turned. 
There is no necessity for any finish on the exterior of 
the field cylinder or any other machine work upon it 
except drilling and tapping four holes in each end to 
take the cap screws holding on the end plates. After 
the field is bored all sharp edges and corners left on the 
polar projections should be neatly rounded off with a 
file. 

The two end plates are exactly alike, each carrying 
a bearing IJ inches in diameter by 3 inches long for 
the armature shaft. They should be cast of bronze or 
gun metal, and need not be more than ^ inch thick. 
In the one at the commutator end four windows should 
be cut, opposite the normal position of the brushes, so 
that these may be observed while the machine is run- 
ning. 



HOME MECHANICS FOR AMATEUES 305 




W77r///77777. 



1 



D 



^ 



m^fmmm^m m^m 







Figs. 282 and 283. Longitudinal and Cross Sections of 
Motor Shell. 



306 HOME MECHANICS FOR AMATEURS 

The brush holder ring, B, Figs. 283 and 285, is of 
brass or bronze, 9^ inches outside diameter and i inch 
thick. It carries the four brush holders, one of which 
is shown in section in Fig. 285 and in elevation in 
Fig. 2S6. Any design of radial brush holder may be 
used, but the simple form shown is easy to make and 
very satisfactory. The body of it consists of a brass 
box, cast in one piece with the stud going through the 
ring, B. This is finished out to allow the coppered 
carbon brush, IJxlfxf inches in size, to slide easily 
through it. A forked piece straddling the upper cor- 
ner of this box carries a finger Avhich is pressed upon 
the butt of the brush by the steel spring and thumb 
screw arrangement shown. 

The dimensions of the shaft are clearly indicated in 
the drawing. The commutator is by far best bought, 
though the drawing furnishes a sufficient indication of 
a simple form to enable an amateur to make it him- 
self if he so desire. It has 48 segments and should be 
4 inches in diameter, 2 inches face, and bored for a IJ 
inch shaft. 

The core of the armature is 6 inches diameter and 8 
inches long. The end plates of steel, -} inch thick, hold 
together the mass of soft iron disks of which it is com- 
posed. These should be a little larger than 6 inches 
diameter in the rough, as the core must finish exactly 
to this figure. If it comes out a little small, the field 
bore, which should wait upon the construction of the 
armature, must be made as nearly as possible A inch 
larger. 

It is useless to japan or insulate the disks. Put 
them together as they are, tighten up the nut, N, Fig. 
285, on the shaft and pin it in place. Then true off the 



HOME MECHANICS FOR AMATEURS 307 

surface in the lathe by very light cuts with a sharp tool 
at rather high speed, using an abundance of soapy 
water on the tool. A mirror-like surface may be at- 
tained in this way. 

While the armature is in the lathe it should be scored 
for the binding wires which will hold the coils in place. 
The grooves for these should be turned, each about 4 
inch wide by a scant iV deep, one near each end and 
one in the middle. 




Fig. 285. Armature Core, Shaft, and Commutator. 

The next operation is milling out the slots for the 
winding. There are 48 of these, each i inch wide and 
^ inch deep, equidistantly spaced around the core. In 
milling out armature slots, the tool should turn at a 
fairly high speed, the feed be very slow and the cut 
light, and an abundance of oil should be used. If no 
milling machine is at hand, the slots may be planed, 
great precaution being taken to keep the cut very light 
indeed. 

The best w^ay to line up the frame of the motor and 
to be sure that the armature is properly centered in the 



308 HOME MECHAXICS FOR AMATEURS 

field bore, is to wrap the armature core with one or two 
layers of thin paper, until it fits neatly in the field 
bore, put on the heads at the ends of the machine, and 
cast Babbitt metal in the bushings. If the end plates 
are marked so that they can be put back in the same 
way, the armature will be found to be correctly cen- 
tered. Unless this is done the electrical balance of the 
motor will be disturbed, and the brushes will probably 
spark and give trouble. 

The winding to be described is of the sort known as 
a four-pole lap winding, and is one of the simplest and 
easiest to make of the various forms of interlocked 
windings. Each of the forty-eight coils used is shaped 
in the forming apparatus shown in Figs. 287, 288 and 
289. This is in two parts, a frame for winding the 
coils and a former for bending them. The frame is 
simply a piece of board with two i inch round metal 
pins driven in it, these being lOf inches apart, out to 
out. Around these, as clearly shown in Figs. 288 and 
289, are wound six turns of No. 14 B. & S. gauge double 
cotton-covered wire, the starting end of the coil being 
marked by twisting a loop in it, as shown in Fig. 289. 
The ends of the wire should be left longer than the illus- 
tration shows them, say about 6 inches. When this 
coil is completed, it should be tied in at least four 
places with small thread to keep it in position when it 
is removed from the two pins, and it should be well 
shellacked with rather thin varnish. It is extremely 
advisable to make up at least five or six of the boards 
shown in Figs. 282 and 283, as this enables the winder 
to allow the coil to dry to the proper consistency of 
"tackiness" before it is removed from the frame, and 
also permits the coils to be made much more rapidly 



HOME MECHAOTCS FOR AMATEURS 



309 



than if it were necessary to wait each time for the wire 
to dry out before winding the next. 

The correct state of dryness of the shellac for the 
next operation must be learned by experience. It is 
when it is at its stickiest. When this condition is 
reached, the coil is removed from the frame and placed 
in the apparatus shown in Fig. 287 to be formed. This 
machine is made of a wooden base board, on Avhich is 
screwed a hard wood shaping piece of the dimensions 
shown and about J inch thick. Two hinged pieces, as 
shown, are provided, so that when the straight coil as 



r^ 





^- 




Fig. 286. 
Brush Holder. 



Figs. 287, 288, 289. 
Board for Forming and Bending Coils. 



it comes from the winding board is laid centrally upon 
the forming piece, and both the hinged pieces bent 
over, it will be bent into a form somewhat like a wide 
inverted U. The illustration shows a coil of only one 
layer being bent. There will be, of course, six wires in 
each side of the coil, or twelve in all to be bent. 

When this bending operation is completed, and be- 
fore the shellac is finally hard, the bent coil must be 
pulled apart so that six of its wires, those tied to- 
gether on one side, may be laid in a slot of the armature, 
and the remaininor six wires, formino: the other Ions: 



310 HOME MECHANICS FOE AMATEURS 

straight side of the bent coil, laid in the slot 90 degrees 
away. In other words, the coil, when it is put on the 
armature, must reach from slot 1 to slot 13, assuming 
that they are consecutively numbered. The appear- 
ance of the finished coil, ready to put on the armature, 
is indicated by Fig. 290. 

A glance at Fig. 291, which shows the end of the arm- 
ature partially wound, will make this clearer. The 




Fig. 290. Completed Coils, Ready to be Mounted on Armature. 




Fig. 291. End of Core, Showing Arrangement of Coils. 

coils, if properly bent, will lie close together on the 
heads of the armature and produce the very neat and 
simple interlocked end arrangement shown in the il- 
lustration. 

When all the forty-eight coils are in place, the arma- 
ture is ready for banding. In the shallow scores on 
the surface are laid thin strips of mica, the armature 
being in centers on the lathe for this operation, or 



HOME MECHANICS FOE AMATEURS 311 

otherwise mounted so that it can be turned around. 
It is better to catch the mica strips under a cord 
wrapped around tlie core a few turns than to attempt 
to stick them on with shellac. On the mica is Avound 
the band, consisting of about No. 24 gauge German sil- 
ver or hard brass wire wound under the strongest ten- 
sion it will stand. The band should net be more than 
Tg inch wide, the number of turns depending, of course, 
on the gauge of the band wire. Above all, care must 
be taken not to have this so large or the mica so thick 
that the bands project above the armature surface, as 
the clearance space is very small and the bands are 
liable to injury in putting the armature in place or re- 
moving it. 

When the band wire is wound on, it is soldered wnth 
five or six little dabs of solder, not continuously, and 
the ends cut off. Three bands will be required, one 
within about ^ inch of each end of the armature core 
and the other at the middle. 

The commutator is held from turning on the shaft 
by a feather (not shown in the illustrations), and is 
sufficientl}^ held endwise by the ninety-six Avires sol- 
dered into it. To connect these, take the beginning 
end of any coil, marked by the little loop twisted in it, 
and solder it and the ending end of the next coil in 
regular order, either way, into the slot in the tail of 
the commutator bar nearest in line. Proceed around 
the armature in this regular order, being very careful 
to bring the ends out neatly and not to pull the head 
of the winding to pieces in so doing. No acid should 
be used as a flux in soldering commutator connections. 
The only safe thing is rosin. A narrow edged solder- 
ing iron that will go into the slot in the commutator 



312 HOME MECHANICS FOR AMATEUES 

bar will be found very convenient for this work. It is 
well to wind some tape around the inner hub of the 
commutator before beginning the soldering. When it 
is finished, a layer of stout cord should be wound on 
over the bunch of ends going to the commutator to keep 
these from spreading from centrifugal action when the 
armature is running. These commutator connections, 
ready for the cord wrapping, are shown in Fig. 292. 

The armature is completed by being returned to the 
lathe, where a light cut is taken over the commutator 




Fig. 292. End of Completed Armature, Showing 
Commutator Connections, 

to true it and cut off any straggling wire ends. The 
armature should be baked over night in an oven to 
thoroughly dry it out before it is attempted to use it in 
the motor. 

On each of the four poles of the field is fastened, with 
small brass angle x)ieces, as clearly shown in Figs. 282 
and 283, a coii consisting of twenty-five turns of No. 
6 B.& S. gauge wire, arranged in five layers of five turns 
each. These coils are wound on a wooden former and 
taped. Their inner ends should be marked in some 
convenient way, and they should be connected to- 



HOME MECHAOTCS FOE AMATEUES 313 

gether so that tliey magnetize the fields alternately 
north and south when a current is sent through the 
four in series. Calling them A^ By C, and D, this is 
done thus : Bring out the outer end of .4 through a 
hard rubber bushing in the commutator end plate (the 
end plate at the commutator end of the motor), then 
connect the inner end of A to the inner end of B, the 
outer end of B to the outer end of C, the inner end of 
C to the inner end of Z), and bring out the outer end of 
D through another bushing. 

Two other bushings are provided for bringing out 
the ends of the wires to the brushes. The four brushes 
are connected in two pairs, opposite brushes being con- 
nected together and to one of the leading-out wires. 
These connections should be made with No. 8 wire and 
the leading-out wires should be No. 6 flexible rubber 
insulated cable. 

Should it be desired to construct motors of this type, 
but of less power, the same general instructions should 
be followed, the diameter of the armature and casing 
being the same, but their lengths different. Below are 
given dimensions and speeds for motors of two and 
three horse power; where a dimension is not given, it 
is the same as that described above for the motor of 
four horse power. The slots for the three horse power 
armature should be J inch wide and | inch deep; for 
the two horse power armature, \ inch wide and tV inch 
deep. 

The motor now being complete, the next part of the 
boat's equipment is the controller. The design sho^Vn 
is exceedingly simple and easy to make. Referring to 
Figs. 293, 294, and 295, which show it in section, 
and Fig. 296, which is a diagram of its connections, its 



314 HOME MECHANICS FOE AMATEUES 



construction and operation ^Yill be readil}^ understood. 
It has been thought best not to complicate its con- 
struction by attempting to combine the ahead and 
astern controlling movements with those for speeds, so 
two handles are provided, one giving half the full 
speeds and the other for reversing the boat's direction. 
These are, however, for convenience, mounted at the 
two ends of the cylindrical case of the controller. The 
best material for this is wood. It should be about 10 
or 12 inches in diameter outside, and about 1 inch thick 




( 


n 






n 






'U 


u 



Fig. 293. 

Cross Section of Speed End 

of Controller. 



Fig. 294. 

Longitudinal Cross Section 

of Controller. 



by about 9 or 10 inches long, and is conveniently built 
up in the way described above for the pattern for the 
field casting. It should be of wood on account of the 
insulating properties of that material. 

In this wooden cylinder are mounted two wooden 
disks, about an inch less in diameter than the internal 
measurement of the containing cylinder. These two 
disks are turned by the two handles — the speed and 
direction handles — and carry on their surfaces copper 



HOME MECHANICS FOR AMATEUHS 315 

sectors which are set into the Avood so as to leave a 
smootli surface for rimning imder the connecting 
points. These are well shown in cross section in Fig. 
298, which is a partial cross section of the speed con- 
trolling end of the apparatus. They consist of brass 
tubes about 1 inch in diameter, 4 inches long, and tV 
inch thick, containing a spring and a contact piece 
(brass or copper), fitting the tube neatly and pressed 
by the spring into contact with the surface of the disk. 
Nine of them will be required. 




Fig. 295. Cross Section of Reversing End of Controller. 

At the speed control end of the apparatus the turning 
disk carries two short sectors on opposite sides, these 
being connected together as shown, and two longer sec- 
tors extending through about 80 degrees of the cir- 
cumference. These are also folded over on to the back 
of the disk, as shown by dotted lines in Fig. 286, so that 
two of the spring contacts may also bear upon this sur- 
face. The easiest way to make these sectors is to cut 
the parts out of tV inch sheet copper, and mount them 



316 HOME MECHANICS FOE AMATEURS 

on the Avood with small countersunk wood screws. 
The circumferential and flat parts of the sectors last 
described may well be soldered together after they are 
in place on the disk. In all cases the sector should be 
let into the wood so that there will be no shoulder to 
catch against the spring contact when the disk is 
turned. 

At the speed control end of the apparatus four of the 
spring contact tubes are mounted, bearing upon the 
edge of the disk as shown ; the four being in opposite 
pairs 60 degrees apart. In the interior of the c^din- 
drical case of the controller are two partitions as 
shown in Fig. 294, the one nearest the speed control 
disk just described carrying two of the spring contacts 
bearing on the flat sectors as shown by the dotted lines 
in Fig. 293. These bear at points on the same diameter 
connecting two of the edge bearing contacts. 

At the other end of the controller is mounted the 
mechanism for reyersing, which is shown in partial 
section in Fig. 295. This consists also of a disk carry- 
ing on its edge three sectors, two of them only long 
enough to be entirely in contact with the spring con- 
tacts as shown, and the other long enough to bridge 
two of them, about fifty degrees. Three of the spring 
contacts are mounted bearing on these, 30 degree? 
apart. The long sector is connected to the further of 
the two short ones, while the middle sector is connected 
to the piyot of the disk and thus to the bushing in which 
it turns. As Fig. 294 shows, this is made quite long, 
as this contact has to carry large currents. It should 
not be less than three inches long, the piyot being a 
piece of one inch shafting. 

Eeferring now to Fig. 296, the operations of the con- 



HOME MECHANICS FOR AMATEURS 



317 



troller will be easily understood. It shows the connec- 
tions for half speed ahead. The diagram shows the 
two sides of the controller separated, for the sake of 
clearness, but it is, of course, understood that they are 
no further apart than the two ends of the wooden box 
in which they operate. The fuse shown in the circuit 
between the pivot of the reversing controller and the 
inner spring contact is mounted in the middle division 
of the box, which should have a door for access. It 
should be an ordinary single-pole Dorcelain fuse block 




Fig. 296. Diagram of Controller Connections. 



carrying a fuse blowing at about 75 amperes. For 
the 3 horse power motor it should blow at 60 amperes, 
and at 40 amperes for the 2 horse power motor. 

The controller box is easiest made of some soft wood, 
such as wiiite pine. It should be liberally varnished 
outside and lined inside with asbestos paper, glued or 
tacked in place. The two disks should be of hard 
Avood. On the exterior of the box should be marked 
the positions for the various speeds and directions, or, 
if the constructor feels so disposed, he can mount a 
position cam and roller on each pivot. 



318 HOME MECHANICS FOR AMATEUES 

The controHer may be placed anywhere in the boat, 
but preferably where it can be manipulated by the 
pilot's left hand while he steers with his right. All the 
wiring between the batteries, motor, and controller 
should be run with good quality rubber covered wire, 
No. 4 gauge, and preferably in iron armored conduit, so 
that it may not be disturbed by passengers walking 
on it. 

The 24 cells of battery may be conveniently charged 
from a 110 volt source of supply by the use of a resist- 
ance. This should be of about 3 ohms and is conven- 
iently made of iron wire, about No. 14 gauge. About 
350 feet of it will be required, and this nmy be conven- 
iently coiled up in loose coils and hung in a frame. 
It should not be confined, but allowed to have free cir- 
culation of air, as it Avill warm up considerably. The 
charging current should be about 20 amperes. Full 
charge is determined either by the voltmeter, which 
will then read 50.5 volts- or by the ''boiling" of the 
cells. It is a waste of current to attempt to further 
charge a cell after it begins to ''boil.'' 

If the amateur so desires he may make his own cells, 
but he is likely to have more satisfaction with those 
lie buys. For the larger size of motor described these 
cells should be made with plates 8 inches square, 15 
lead plates and 16 zinc plates to each cell. 



HOME MECHANICS FOR AMATEUES 



319 



THE EDISON DYNAMO Oil MOTOK 

It is one thing to make a dynamo or motor from 
explicit instructions and quite another thing to design 
a machine adapted to generate or be operated by a 
particular current. The former is purely mechanical 




Fig. 297. Small Edison Dynamo or Motor. 

and within the range of most machinists and amateurs, 
while the latter is entirely within the province of the 
electrical engineer or electrician. AA'hen the work of 
machine building proceeds simultaneously with the 



320 HOME MECHANICS FOR AMATEURS 

study of fundamental principles, real progress is made. 
For the benefit of those who proceed in this Avay, and 
in answer to many inquirers, we give a detailed descrip- 
tion of an Edison 0.25 kilowatt machine, designed for 
use as a dynamo for supplying a current for five Edison 
standard lamps, or for use on the Edison circuit as a 
quarter horse power motor. 

Before beginning the description of the machine it is 
but fair to say that it is thoroughly well made in every 
particular. The insulation in every part is very per- 
fect, and the whole is so well made that any single 
machine built by a mechanic or amateur could but 
suffer by comparison with it; and furthermore, we 
doubt if any maker of a single machine could even 
purchase the materials required for the price asked for 
the machine by the regular manufacturers. Therefore, 
if the machine is wanted, we advise a purchase. If 
experience is wanted, the making of the machine comes 
first in order, with a probable purchase to follow. 

The base, which is of brass, is made hollow, as 
shown. It is 14 in. long, 7| in. wide. If in. deep at 
the ends, with two IJ in. elevations at the middle for 
receiving the cast iron pole pieces of the field magnet, 
which are each secured to the base by two small tap 
bolts extending upwardly through the base and into 
the pole pieces. 

The upper surfaces of the pole pieces are truly faced 
for receiving the cylindrical field magnet cores, w^hich 
are made of Swedish iron, 2f in. in diameter and 4^ 
in. long. These magnet cores are each held in position 
by a threaded stud screwed into the pole piece and 
entering magnet core. Each core is provided with a 
vulcanized fiber collar at each end, which is | in. thick 



HOME MECHANICS FOR AMATEUES 321 

and I in. wide. Upon each core, and between the 
fiber collars, is wound 5^ lb. of No. 24 silk-covered 
copper wire, with a wrapping of thin varnished paper 
between the layers. The cores, before winding, are 
thoroughly insulated with the same material. The 




Fig. 298. Side Sectional Elevation of Dynamo. 



fiber collars are each held in place by three conical- 
headed screws entering the end of the core, with their 
heads projecting beyond the body of the core. To the 
inner and outer ends of the winding of each arm of the 
magnet are attached pieces of larger wire to avoid 



322 



HOME MECHANICS FOE AMATEUliS 



breakage, and the iuuer ends are led out through 
grooves in the fiber collars. The yoke, of Swedish 
iron, is 2f in. wide, 2^ in. thick and 7^ in. long. It 
is held in position on the cores by two ^ in. bronze 
studs, each threaded at the upper and lower ends, and 
furnished with a collar which fits into the counter- 




FiG. 299. Side View of Field Magnet, Partly in Section. 

bored part of the hole in the yoke. The studs are 
squared at the upper end to receive a wrench, and a 
nut is placed on each stud above the yoke for clamp- 
ing it securely after adjustment. The machine is regu- 
lated or adapted to any work requiring less than its 
full power by raising the yoke more or less. The yoke 



HOME MECHANICS FOR AMATEUKS 333 

is provided with an eye, by means of which the ma- 
chine may be lifted. 

Front and rear boards of mahogany are arranged on 
opposite sides of the yoke, and held in place by brass 
plates at the ends. 

The outside ends of the field magnet coils are con- 
nected with binding posts on the rear board. 

A variable resistance of ten or fifteen ohms is in- 
serted between these posts when the machine is used 
as a dvnamo. In the front board, at the right hand 
side is secured a bronze casting known as the right 
hand motor head field magnet terminal. This is 




FIG. 300. Switch on the Edison Dynamo or Motor. 

adapted to receive the line wire, also one of the leads, 
the upper end of which is screwed to the casting. The 
lower end of the lead is secured to a lead termina 
attached to a block of wood secured to the right hand 
pole piece. At the right hand side of the machine a 
similar arrangement of the lead is found, but the up- 
per lead terminal is made in two separate parts, one 
attached to the lead, the other being connected with 
the line; both being furnished with copper switch 
tongues. The switch arm turns on a stud projecting 
from the front board and carries a loose triangular 
switch plate of copper, having a knife edge which 



324 HOME MECHANICS FOE AMATEURS 

readily enters between the switch tongues. The switch 
has a T-handle of hard rubber, by means of which it 
is turned. A stop pin projecting from the front board 
limits the rearward movement of the switch arm. 

The inside end of the right magnet coil is connected 
with the right hand lead, and the inside end of the left 




Fig. 301. Diagram of Winding of Edison Armature. 



hand magnet coil is connected with the lower half of 
the left hand lead terminal. 

At opposite ends of the base there are plane surfaces 
to which are secured the self-oiling bearings of the 
armature shaft. Each bearing has a hollow standard 
lurnished with a cap, Avhich, together with a cross 
piece in the hollow standard, forms a support for the 



HOME MECHANICS FOR AMATEURS 325 

spherical central portion of the bronze sleeve forming 
the journal box proper. 

This sleeve is shorter than the outer portion of the 
bearing, and is slotted across the top to allow two 
brass rings to ride upon the armature shaft. These 
rings dip in the oil in the hollow standard, and as they 




Fig. 302. The First Two Coils and Commutator Connections. 

revolve carry oil to the shaft in quantities more than 
sufficient for the purpose of lubrication. The oil is 
distributed throughout the bearing by means of spiral 
grooves formed in the inner surface of the journal box. 
The surplus oil drops back into the hollow standard. 
A screw plug in the lower portion of the standard 
allow^s of the renewal of the oil. The bearings at 



326 HOME MECHANICS FOR AMATEURS 

opposite ends of the machine are alil^e, except that the 
cast iron support of the bronze journal box, at the 
commutator end of the armature, is turned on its inner 
end to receive the brush yoke. 

The steel armature shaft is 16J inches long and i 
inch in diameter at the journals, and H inch in diame- 
ter between the journals. The larger part of the shaft 




Fig. 303. Arrangement of the Layers at End of Armature Core. 

is 9^ inches long. Sufficient end chase is allowed in 
the armature journals to cause the surfaces to wear 
smoothly. 

On the central portion of the armature shaft is 
placed a wooden sleeve, liV inch in diameter; on 
this are mounted the thin sheet iron disks forming the 
armature core. These disks are 2f inches in diameter. 



HOME MECHANICS FOR AMATEURS 



327 



They are arranged in series of five, with tissue paper 
between the disks, and between the series of five are 
placed several thicknesses of paper. Enough disks are 
clamped together on the shaft to make this portion 
of the core 3^ inches long. The cast iron disks be- 
tween which the sheet iron disks are placed are ^ inch 
in thickness and 2J inches in diameter. One of them 
is fixed on the shaft, the other being held in place by a 
hexagonal nut screwed on the shaft. The cast iron 
disks have their outer corners rounded, and in the 




Fig. 304. The Ends of the Armature Core. 



edge of each are formed thirty-two equidistant radial 
slits tV inch wide. In these slits are inserted slips of 
vulcanized fiber for separating the different pairs of 
coils during the operation of winding. 

It is impossible to describe the Edison winding with- 
out depending mainly on the diagrams, Figs. 301 and 
302. There are two series of coils ; that is to say, there 
are two coils in each division of the armature There 
are thirty-two bars in the commutator, which are num- 
bered consecutively from 1 to 32. 



328 HOME MECHANICS FOR AMATEURS 

The armature core and shaft are thoroughly insu- 
lated by means of paper coated with an adhesive var- 
nish. Jute string ribbon is wound on the face of the 
core as a further protection. 

The wire used on the armature is No. 21 copper wire, 
double covered; the inner covering being of silk, the 
outer of cotton. 

i^eaving an end out for connection with the commu- 
tator coil, No. 1 is begun at 1 and wound in four lay- 
ers, with six convolutions in each layer, the outer ter- 
minal coming out at 1'. These ends are marked re- 
spectively 1 and 1' in such a manner as to avoid any 
possibility of the detachment of the marks. If this 
caution is observed, much trouble may be avoided. 
A good way to mark them is to place a tag of parch- 
ment, or parchment paper, on each end of the wire, 
with the number marked on. 

After winding coil No. 1 the armature is turned half 
w^ay over and coil No. 2 is wound and marked in the 
same way, with 2 on the inner end of the coil and 2! on 
the outer end. The coil is then reversed and coil No. 
3 is wound and its ends are marked in the same w^ay, 
and so on until the first series of coils is finished, the 
last coil of the series being marked 16 and 16'. 

The first coil of the outer series is No. 17-17'. This 
is wound on the top of coil No. 1. The armature is 
turned over and No. 18 is wound on the top of No. 2, 
and so on until all of the outer coils are in place. 

Before winding, the inner end of each wire is 
wrapped in jute string ribbon to a point within the 
end of the armature core, and it is further protected 
by a TNTapping of thin adhesive tape. The outer end of 
the coil is covered in the same way. 



HOME MECHAISTICS FOE AMATEURS 329 

About three pounds of No. 21 wire are required for 
the armature. The length of wire in the first inner 
coil is 26 feet 6 inches. The length of wire in the last 
outer coil is 35 feet. 

The commutator cylinder* is formed of 32 bronze 
bars having beveled ends and radial arms for receiv- 
ing the wires. These bars are clamped in position on 
a sleeve having an under-cut flange, by a countersunk 
washer and a nut screwed on the sleeve. Mica is 
inserted between the commutator bars, between the 
bars and the sleeve, and between the ends of the bars 




Fig. 305. The Armature with Parts Broken Away. 

and the flange and the washer. The radial arms ex- 
tending from the commutator bars each have a slot in 
the end for receiving the terminals of the coils. 

The coil terminals are arranged in groups of 16, the 
wires of each group being parallel. The terminals are 
carried around and attached to commutator bars 
which are about 90° from the planes of the coils to 
which they belong, thus maldng the winding more 
symmetrical and at the same time permitting of a bet- 
ter arrangement of the brushes. 

The coil terminals are inserted in the slots of the 
arms of the commutator bars and soldered with soft 
* For further points on Commutators, see Supplement 600. 



330 



HOME MECHANICS FOR AMATEURS 



solder, the connections being made in accordance with 
the diagram, Fig. 301. 

The wires, where thej cross at the back and front 
end of the armature, are separated by sheets of mica. 
Where the winding crosses at the rear end of the arma- 
ture the wires are spread out so that they are only 
one layer deep. 




Fig. 306. The Brush Yoke. 



When the winding of a coil is finished, the terminal 
is fastened by stout threads inserted in the coil before 
winding the last three convolutions, and tied after the 
coil is complete. 

A vulcanized fiber collar, a little larger in diameter 
than the commutator, is slipped over the commutator 
bars and placed against the radial arms of the bars 
as shown. The edge of the collar is grooved and a 
canvas cover is fastened to the collar by tying it in 
the groove. It is then drawn over the terminals and 



HOME MECHANICS FOR AMATEURS 331 

fastened by the first ring of binding wire on the arma- 
ture. At the opposite end of the armature a similar 
collar and cover are provided. 

Before covering the terminals with the canvas they 
are wound with twine to give the end of the armature 






Fig. 807. Details of the Brush Holder, the Commutator Cylinder, 
and Brush-holding Jig. 



a symmetrical shape. The winding is varnished with 
shellac before its cover is applied, and the cover is 
varnished after it is secured in place. 

The binding rings are formed of brass wire, wound 
tightly over a layer of mica interposed between the 
wire and the binding. The binding wire is secured by 
clips and soft soldering. 

The brush yoke is provided with wooden handle by 



332 HOME MECHANICS FOE AMATEURS 

which it may be moved and a binding screw by which 
it is clamped in the position of use. In mortises in the 
ends of the yoke are placed insulating blocks, in which 
are inserted the brush-holding studs. These studs are 
each provided with a nut for clamping the brush 
holder cables which communicate with the leads at the 
side of the pole pieces. 

On each brush-holding stud is placed a sleeve fas- 
tened with a set screw, also a loose sleeve connected 
with the fast sleeve by a spiral spring concealed with- 
in it. The loose sleeve is furnished with a brush clamp 
for holding the brush, which bears on the commuta- 
tor cylinder with a yielding pressure. The brushes are 
formed of spring copper wires fastened together at 
their outer ends with soft solder. 

A jig goes with each machine for clamping the brush 
and guiding the file while renewing the brush ends. 

The speed of the motor on a 125 volt circuit is 2,400 
revolutions per minute. The speed at which the arma- 
ture is to be driven in order to generate a current hav- 
ing an E. M. F. of 125 volts is 2,730 revolutions per 
minute. 

According to the new rating the machine here de- 
scribed is a 0.5 kilowatt machine, which, when used as 
a generator for supplying lights, will generate suffi- 
cient current to bring to full candle power nine 16 C. 
P. 112 volt lamps, and when used for power it is a | 
horse power motor at a rated volt. It is guaranteed to 
give 0.47 horse power at | of its rated volts. 



HOME MECHANICS FOR AMATEURS 333 

THE UTILIZATION OF 110 VOLT ELECTRIC 
CIRCUITS FOR SMALL FURNACE WORK* 

It occurred to the writer in wiring up a couple of 
experimental arc lamps across the feeders of an in- 
candescent lighting system, that a laboratory electric 
furnace could be operated on a series carbon plan, 
without disturbing the protecting fuses of the circuit. 
This idea of concentrating a pair of arcs within a 
small crucible or furnace, using only the amount of 
resistance wire located in the tops of the lamps, proved 
to be crude, the current taken being excessive upon 
introducing a charge for fusion, when its character 
embodied fair electrical conductivity. In order to 
obviate this difficulty, as well as to compensate for the 
lowering of resistance due to eddy currents between 
the carbons, a triple series arc was formed requiring 
only a short length of German silver wire to steady 
its action. With this arrangement the most success- 
ful results were attained, and with the furnace, as 
finally constructed upon this plan, many metallurgical 
processes were carried on, a 12 ampere fuse placed in 
each leg of the current supply being sufficient. The 
little furnace illustrated in Fig. 308 is capable of pro- 
ducing calcium carbide in twenty minutes from the 
time the current is switched on, the fuses remaining 
intact throughout the operation, if a short length of 
resistance wire is introduced into the circuit. With 
this arrangement it is possible to separate the carbon 
electrodes 3^ inches without extinguishing the triple 
arc. It is the intention of the writer to describe in 
detail the construction of this little plant, and fur- 
* By Nevil Monroe Hopkins. 



334 



HOME MECHANICS FOE AMATEUES 







HOME MECHANICS FOR AMATEURS 335 

nish carefully prepared directions for making small 
quantities of calcium carbide. This compound is 
chosen because of its exceedingly useful and interest- 
ing characteristics, and because of the numerous in- 
quiries the writer has received in regard to its forma- 
tion on a small scale. Calcium carbide is a highly 
refractory body, its preparation requiring the highest 
temperatures, and its successful production by means 
of this small electrical equipment urges experimenta- 
tion with other compounds requiring less energy and a 
lower temperature. 

Fiff. 309 will enable us to understand the mounting 
and connecting of the carbons, being a plan view of 
the system. The steps in putting together this little 
equipment should consist in forming and lining the 
furnace proper. The shell is made from sheet iron, 
cut to exactly incase one of the common sizes of fire 
clay slabs. The exact size and shape of this furnace 
is, of course, immaterial, provided the length is not 
over 13 inches from end to end, as shown in Fig. 311. 
Should the length exceed 13 inches, standard electric 
light carbons would not prove long enough to meet at 
the center. As the fire clay slabs adapted to our pur- 
pose vary somewhat in length, definite dimensions are 
not given, but those shown in Fig. 310 will be found 
useful as guides, and are approximately suited to the 
average sized slab sold for backing up fire places and 
stoves, which are plane on one side and fluted on the 
other. Having procured four of these slabs, the sheet 
iron (No. 18 or 20 gauge) may be marked off carefully 
and bent to form the shell. The overlapping sides are 
drilled through and securely riveted together. One of 
the fire clay pieces is now placed in the shell on either 



336 HOME MECHANICS FOE AMATEURS 




C I 



O 



MM I I I II 



"1 



I I I I I I 13] 





II ' 1 




















































• • ^ 












! 1 ^ 
























\ 































> 
o 
O 

bo 

fl 

'3 
rt 
a 
d 



HOME MECHANICS FOR AMATEURS 337 

side (the fluted surface next to the iron) and a large 
fire brick drojjped in between them. These large fire 
bricks come with a recess in the top, as represented 
in Fig. 308, Avhich is desirable for collecting small 
fusions. If the three pieces of fire clay fit nicely in 
the shell, the fire brick is removed temporarily, and 
our attention given to cutting one of the slabs in half 
to form the ends of the lining. 

In Fig. 310 a section of the shell is shown, where A 
represents one of the side slabs in position, running 
from end to end, as illustrated by the horizontal shad- 
ing. These slabs may be had about 12| inches in 
length by about 8 inches in width and 2 inches thick, 
which serve for this lining nicely. The end pieces 
must be cut off at an angle to form the bottom of the 
incline leading into the furnace. These are repre- 
sented in the drawing by section, in oblique lines. The 
fire clay is cut with a cold chisel and hammer, w^ork- 
ing slowly with uniform blows, exercising some little 
patience, until the pieces have the proper shape. The 
angle must be determined by trial with the shell, which 
is cut down by means of heavy shears, within 5 inches 
of the bottom, being about 5J inches in wddth. The 
metal flap, resultant of this cutting down, is sharply 
bent over and cut off, the edge being smoothed with 
a large flat file. A band of iron riveted around the 
top, as illustrated, crowns the opening, and must be 
adjusted as to height, by the size and thickness of 
the fire clay lining which has been procured. 

To complete the furnace proper, it is only necessary 
to put in place the angle pieces, and secure in position 
temporarily four pieces of glass, in order to form the 
top of the inclined entrance. The wooden brace, B, 



338 HOME MECHANICS FOR AMATEURS 

is cut to the proper length to press the vertical glasses 
(shown in simple ruling) against the end pieces of fire 
clay, and small Avooden blocks made to support the 
glass plates on the incline, as illustrated, leaving a 
2-incli space. The height of the vertical glass plates 
must be just equal to the height of the side slab, 
Ay and the inclined pieces must come nicely in 
contact witli them. The two spaces formed, C and 
Dy are now filled in with ^^stove fix-' or other fire clay 
compound made plastic by the addition of a little 
water. This compound may be had ready to mix, and 
is applied with a trowel. The glass plates must be 
left in position over night, in order that the material 
which they support may set. They are then with- 
drawn together with the wooden brace, and the fire 
brick dropped into the bottom to stay. An additional 
quantity of the stove compound is made up, and all 
cracks and crevices plastered in. When this finally 
sets, a strong and durable furnace is produced. It 
should be heated up slowly for the first time uncovered, 
in order to expel all moisture. The top, which con- 
sists of the fourth piece of slab, is cut through by means 
of the cold chisel, and is afterward smoothed with a 
large rasp. 

The method of suspending the cover is illustrated in 
Fig. 311, the iron bands coming over the fire clay walls, 
on the inside, being thus protected from the heat of 
the arcs. Having completed this portion of the work, 
the base, platforms, and screw feed must be put to- 
gether. The base, upon which the entire plant rests, 
consists of a heavy pine board, 4 feet in length by 8 
inches in width. The furnace is mounted upon three 
common bricks (2^ inches in height) and placed at 



HOME MECHANICS ¥011 AMATEURS 339 

the center of the board to facilitate the design and 
construction of the inclines, which must be very ac- 
curately pitched, in order that the carbons may be fed 
into the furnace Avithout coming in contact with the 
openings. Should they touch, however, a couple of 
mica sheets must be applied as a precaution against 
short circuits. These inclines are made from 1 inch 
pine boards, 6 inches in width and 16 inches in length. 
These boards are mounted upon upright pieces of wood 
of the same weight for trial, but are not screwed on 
until the screw feed is put in place, which is attached 



/] A 

I. .3- 

8 ^^1^ *• 



1=3 



Fig. 312. Sections of Clamp as applied to Screw Feed. 



from underneath. Of course the inclines must be care- 
fully adjusted to any specific furnace, but the height 
of the front and back supports will be about 8 and 3^ 
inches respectively. These may be attached at once by 
means of strong angle irons as illustrated in Fig. 308. 
To form the screw feed, select a large sized furniture 
maker's clamp, with Avooden screws at least 18 inches 
long. Fig. 312 illustrates such a clamp, the sections 
to be sawn through to make the bearings and screw 
collars being marked in dotted lines. The sections 
marked S S will be found to contain the screw threads, 
and serve for the center traveling pieces upon which 



340 HOME MECHANICS FOE AMATEUES 

the blocks and electrodes are mounted. The sections 
1, 2y 3, and 4 serve for simple bearings, after being 
carefully drilled through with a bit and brace, ex- 
ercising great care in boring, to secure centrally located 
straight holes. These are screwed on to the board 
from underneath, and as the wood from which the 
furniture clamps are made is very hard, gimlet holes 
must be provided for the reception of the screws to pre- 
vent splitting. These gimlet holes must have consider- 
able depth. Upon the traveling pieces are mounted 
two blocks 6 inches long, 4 inches wide, and about 1^ 
inches in thickness. Three brass tubes are carefully 
mounted upon each of these, of the right size to receive 
electric light carbons (the longest kind, copper coated) 
with a tight fit. These tubes are secured as shown in 
Fig. 309 by means of heavy brass straps. The car- 
bons are placel in position, about an inch of the end 
left protruding to allow brass spring clips to be pushed 
underneath. With this spring adjustment, the car- 
bons can be quickly withdrawn or easily regulated. 
The connections, which should consist of double in- 
sulated wires (No. 16 gauge), are soldered to these 
clips in the manner indicated. It will be observed by 
referring again to Fig. 308 that the carbons may be 
slowly withdrawn by turning the screw, or they may 
be pulled out of the furnace by the handle of the screw 
when it is necessary to remove the furnace from the 
base. 

The furnace is now ready for connecting up and a 
trial. Adjust all six carbons carefully, making sure 
that they are all in contact. When the triple arc once 
forms, they require very little attention, and, as stated, 
will continue to burn when the distance between their 



HOME MECHANICS FOR AMATEUES 341 

ends exceeds 3 inches, Avith a charge of coke and lime 
as the conducting medium. Fig. 313 shows the scheme 
of proper connections with a 110-volt electric lighting 
sj^stem. The main conductors, or feeders, are repre- 
sented at the bottom by heavy horizontal lines and are 
joined as indicated direct to a porcelain fuse block, F. 
This connection should be made as near tlie meter as 
possible, in order to avoid annoyance from intermedi- 
ate fuses. In addition to this, the capacity of the meter 




Fig. 313. Diagram of Connections, with Ammeter and Voltmeter 

arranged for studying the Behavior of Compounds 

within the Arc. 



should be ascertained, which should allow of a 25 am- 
pere load. In other words, a 45-light meter will be 
large enough, a standard 16 candle power lamp taking 
about 0.6 ampere. Place a 12-ampere fuse in each side 
of the fuse block, as shown, and join the same to a 
small knife switch, /s'. Should the reader possess an 
ammeter (of fully 50 amperes capacity), it should be 
included in the circuit, and a voltmeter should be 



3^2 HOME MECHAmCS FOR AMATEURS 

joined across the connections of the arcs if possible. 
The resistance, R, consists of 20 feet of doubled Ger- 
man silver wire, No. 22 gauge, Brown & Sharpe.* 

To make this resistance in convenient shape, the 
wire should be wound about a large fire clay slab, 
which serves for sufficient insulation and resists the 
effect of the heating up. This slab with its wire must 
not be placed near woodwork. The furnace should be 
run for fifteen or twenty minutes, for the first time 
without its cover and without a charge, moving the 
carbons back and forth and testing their centering, etc. 
Should the arc go out, the feed is screwed down until 
contact is again made and the incline rapped with a 
mallet in order to cause the points of the carbons to 
vibrate or rub together. In doing this work with the 
cover off, use strongly smoked glasses to protect the 
eyes from unnecessary strain. Having mastered the 
handling of the equipment we are now ready for 
experimentation, and will proceed direct with the prep- 
aration of calcium carbide. To produce a laboratory 
quantity of this compound, follow closely the direc- 
tions given. Weigh out 18 ounces of good unslaked 
lime (calcium oxide, CaO), and reduce to a granulated 
form in a large iron or porcelain mortar. Phice this 
portion of the charge on a large sheet of manila paper 
and prepare for the grinding of the coke. Do not at- 
tempt to use charcoal, as it is too light and floury, 
oxidizing away in the air without combining with the 
lime. 

Select either good coke or procure a lot of broken 
electric light carbons, and weigh out 16 ounces of the 

* This wire requires much care in handling, and, if allowed to 
tangle or kink, breaks very easily. It is very brittle. 



HOME MECHAMCS FOE AMATEIJES 343 

fragments. These must now be pounded to small 
pieces and afterward granulated in the iron mortar to 
about the same size as the pieces of lime. The coke 
and lime should now be thoroughly mixed together on 
the large sheet of paper preparatory to grinding in an 
iron coffee mill. These mills come all of iron, designed 
to screw up against the wall, and are equipped with a 
regulating device for grinding coarse or fine. The 
money put in a mill of substantial character will be 
well invested, as it will prove of great value in a 
laboratory or experimental shop for reducing many 
substances to powder. The granulated lime and coke 
are poured into the mill and ground to the finest meal, 
passing the mixture through several times to insure an 
intimate mixing as well as a fine powder. Should a 
mill not be at hand, the charge may be reduced to the 
proper fineness, although requiring much more labor, 
by means of the large iron mortar. The pestle of the 
mortar is ground to the right and the mortar rotated 
to the left with the palm of the left hand. There is a 
little knack in doing this, and with a little practice, 
but with considerable work, the lime and coke may be 
suitably prepared for fusion. 

The powdered charge must be put away in airtight 
receptacles, if it is not intended for immediate use, as 
the lime in the finely powdered state quickly slakes if 
left in contact with the air. Should we use the mix- 
ture without thoroughly grinding, which is a very 
dark slate color, it will be found a very light gray 
upon shutting down the furnace after a run, showing 
that most of the carbon has gone off as carbon dioxide 
and carbon monoxide, leaving the unfused lime behind. 
We can now start the furnace for actual work and 



344 



HOME MECHANICS FOE AMATEURS 



feed four or five ounces of the charge in the arc as 
soon as well started, observing the voltmeter and am- 
meter, if a study of the resistance of furnace fusions 
is to be made. The carbons are drawn gradually apart, 
and additional quantities of the charge added from 
time to time. The cover is kept on as much as possi- 
ble, only removing it to add more material and to heap 




Fig. 314. Furnace for making Solders and other Alloys having 
Low Melting Points. 

the compound about the triple arc by means of a 
spatula. After a twenty minutes' run, during which 
time the compound is frequently heaped about the 
points of the electrodes, the switch may be opened 
and the furnace allowed to cool. Should one of the 
fuses bloAv out during the run, it should be immedi- 
ately replaced by one of the same capacity and a small 



HOME MECHANICS FOR AMATEURS 345 

amount of additional German silver wire added to the 
circuit, although the 20 feet of the double material will 
probably afford all the protection necessary and steady 
the arcs in a very satisfactory manner. 

A variable rheostat of low resistance included in the 
circuit would be a great convenience, allowing the cur- 
rent flow to be adjusted to the capacity of the fuse 
wires to a nicety. A few runs with the furnace will 
enable one to become quite expert in forming calcium 
carbide, working with a 3-inch arc without allowing it 
to go out. When the furnace has cooled, a number of 
large masses of the carbide will be found in the bot- 
tom of the fire brick hearth, which may be thrown 
immediately upon water to obtain acetylene gas or 
stored away in airtight cans or jars for future use. If 
left open in the air, it is slowly attacked by moisture 
and is decomposed. Before suggesting other work for 
small preparations, the introduction of a very small 
crucible furnace may be of interest. Fig. 314 illus- 
trates the simplest form of crucible equipment de- 
signed for operation on the 110-volt circuit, with six 
or eight 32 candle power lamps arranged in a bridge 
in multiple as indicated. A large sand crucible or or- 
c^Jnary flower pot is filled with granulated fire clay or 
other poor conductor of heat, and a smaller crucible 
placed inside. The whole is stood on a fire brick and 
the large pot or crucible is provided with a clay cover 
having holes for the reception of two carbon electrodes. 
The stands sold for supports in chemical laboratories 
make the most convenient holders for the carbon rods. 

The furnace depicted in Fig. 315 is capable of doing 
more work, in fact, as much as may be wished for on a 
small scale, if the experimenter is so situated that he 



346 



HOME MECHANICS FOR AMATEURS 



may have as much current as he wants. The small 
crucible is drilled through the bottom, and one of the 
electric light carbons cemented in place, or simply held 
in position by a tight fit. The outer incasement in 




Fig. 315. Furnace for melting Brass, Copper, etc., for Harder Alloys, 

and reducing Small Quantities of Metallic Oxides 

to their Respective Metals. 

this design consists of a large flower pot, supported 
on a small iron ring stand, also to be had from chemi- 
cal dealers. This is covered by a heavy plate of mica 
with a central hole for the carbon. By putting in 
series two or three rheostats the current may be easily 



HOME MECHANICS FOE AMATEURS 347 

controlled, and if heavy fuses are installed, and if 
there is no fear of injuring any meter, a very fierce 
and intense arc may be maintained. Use only the cop- 
pered carbons, and solder their connections to them. 
The writer suggests experimentation with alloys, in 
connection with these small crucibles (sand crucibles, 
plumbago, or graphite), using borax in some cases and 
charcoal in others (here the light floury charcoal is 
to be preferred), in order to fuse the bodies in a neutral 
atmosphere. 

By using an excess of charcoal constantly in the 
crucible, the inert carbonic acid gas which is formed 
will expel the oxygen from the crucible and prevent 
oxidation of the metals experimented with. Nearly 
all the metallic oxides may be reduced in the presence 
of carbon with a sufficiently high temperature, provid- 
ing an interesting field for work. Small masses of 
aluminum and aluminum bronze may be formed in 
the crucible furnace illustrated in Fig. 315, or in the 
large triple arc equipment, although only on a very 
small scale. Aluminum oxide (AI0O3) may be directly 
reduced in the arc in the presence of carbon by intro- 
ducing an intimate mixture of the oxide and powdered 
graphite. The aluminum oxide may be bought, or may 
be prepared on a very small scale from clay or alum 
as follows : Digest 8 ounces of clay in a mixture of 
hydrochloric and sulphuric acids in a glass flask ( HCl 
3 parts, H.SO4 1 part) for about an hour. The fluid 
is mixed with four or five ounces of water and filtered. 
An excess of ammonia (ammonium hydroxide) is 
added, and the white precipitate collected on a large 
filter and allowed to dry. It is then mixed with the 
graphite and the two ground together. From alum, it 



348 HOME MECHAmCS FOE AMATEURS 

is only necessary to add the ammonia to a strong solu- 
tion of alum in water, and treat the resultant precipi- 
tate in a like manner. Of course this process is only 
a little chemical exercise, and is only given for the 
benefit of those who wish to attempt the entire process, 
although of no commercial value, the manufacture of 
aluminum embodying entirely unlike methods. 

For the benefit of those who have never experimented 
with the electric arc, the writer includes in the sug- 
gestions offered a pair of strongly smoked glasses, to 
be worn whenever the arc is exposed. To work with- 
out glasses is to expose the eyes to severe strain and 
possible injury. 

EECORDING TELEGEAPH FOE AMATEUES 

If the question of utilit}^ controls one in making and 
trying a piece of apparatus, it is useless to expect to 
realize anything in the way of profit from the record- 
ing telegraph illustrated and described; but a few in- 
terested amateurs can co-operate, and with a wire and 
transmitter for each can secure a practical knowledge 
of the workings of some of the large telegraph systems 
and of some of the applications of electricity, which 
could not be secured in any other way. The expense 
would be slight, when there is a joining of amateurs 
for one purpose. 

It is assumed that an ordinary sounder is available 
for the central office recorder, and that every sub- 
scriber will furnish a transmitter, a wire to communi- 
cate with the central office recorder, and battery suffi- 
cient to operate one branch of the central office system. 

In making the central office recorder, a common 
sounder is pressed into service. It is provided with a 



HOME MECHANICS FOE AMATEUES 349 

stylus-holder which is clamped to the free end of the 
armature lever. The stylus is a piece of steel wire 
1-16 inch in diameter and 1 inch long, with a rounded 
and hardened point. It is clamped in place by a set 
screw. 




Fig. 316. 
The Receiving Instrument of the Recording Telegraph. 

Under the free end of the armature lever is journaled 
an arbor, carrying a wooden roller having a V-shaped 
peripheral groove at the center, exactly under the 



350 HOME MECHANICS FOE AMATEUES 

stylus; so that when a paper strip passes over the 
roller, the stylus can make a slight depression in the 
paper, when the sounder magnet is actuated. 

The principal features of this telegraph are a sim- 
ple transmitter for giving fixed calls, like a call box, 
and the mechanism for carrying the paper tape over 
the grooved spool and under the stylus. The roll of 
tape as purchased from the dealer is carried on a 
wooden reel, supported by a standard at the rear of 
the sounder. Between tAVO standards in front of the 
sounder are journaled two rollers, a h. The roller a 
is flanged and provided on its periphery with three or 
four rubber bands, to give it frictional contact with 
the paper tape. The lower roller h is covered with a 
piece of rubber tube and the shaft of this roller carries 
a small governor c, for regulating the speed of the 
tape. The tape extends over the roller h, thence down- 
ward under the flanged roller d, then upward to a 
fastener. The roller d is provided with a weight which 
actuates the mechanism. 

It will thus be seen that the paper tape is carried 
through the machine by the action of the weighted 
roller d, and its motion is regulated by the governor c. 
The governor c consists of a slotted hub /, links g g, 
pivoted in the slots of the hub, a slotted sliding block 
/i, placed loosely on the shaft of the roller h, weighted 
arms l i pivoted in slots in the block h^ and pivotally 
connected to the outer ends of the links g g, and a light 
spring, ;'-, tending to draw the weighted arms i i toward 
each other. The block h is provided with a leather 
washer /, which produces necessary frictional contact 
with the standard, when the weighted arms are thrown 
out by centrifugal action. The tape reel is provided 



HOME MECHANICS FOE AMATEURS 351 



with a slight spring for cheeking its motion when the 
paper feed stops. In the side of the block which car- 
ries the stylus is inserted a small stud, in which is 
clamped a wire ni, having its free end near the side of 




Fig. 317. Diagram of the Receiver, 

the roller a, flattened and turned up at right angles. 
The flattened end of this wire m lies in the path of a 
small pin projecting from the roller «^, so that when- 



352 HOME MECHANICS FOR AMATEUES 

ever the armature lever is drawn down b}^ the magnet, 
the pin is released, and the roller a is allowed to turn, 
but when no current passes the magnet, the armature 
lever rises and brings the flattened end of the wire m 
into the path of the small pin, and stops the movement 
of the roller a, and consequently arrests the progress 
of the paper, until the pin is released by another ac- 
tion of the armature lever. Binding j^osts placed at 
the rear of the sounder are connected with the magnet 
electrically in the usual Ava^^ To transmit a signal 
over a line connected with this instrument, it is not 
necessary to understand the telegraph alphabet, nor to 
know anything in regard to telegraphy. The signals 
are pre-arranged, so that the operation of sending is 
purely mechanical. 

The signal board shown in detail in Fig. 318 was 
invented and patented years ago by William Hadden, 
but the patent has long expired. This simple device 
consists of a board, a few inches wide, and perhaps 
twice the length, depending on the number and length 
of the messages sent. The board here shown is 4^ inches 
wide, 7 inches long, and J inch thick, with as many 
longitudinal grooves formed in it, as there are signals 
to be given. The signal board must be of very hard 
wood, and the dots and dashes of the signals are formed 
by sewing No. 30 plain copper wire through holes ex- 
tending through the board, from the grooves in front 
to the grooves in the rear. As the signal transmitter 
is at present constructed, the copper wire sewed 
through the first set of holes represents the letters of 
the Morse alphabet from A to F, with a dash between 
each letter. The sewing in the second groove repre- 
sents the letters from G to J, The sewing in the third 



HOME MECHAXrCS FOR AMATEURS 



353 



groove represents tlie letters from K to .]/, and so on. 
All of the wires forming these letters are connected 
together at the top of the board, by a wire on the back, 
which is in electrical connection with the binding post 
seen to the right in onr vi(nv of the signal apparatus. 
The binding ])ost at the opposite edge of the board is 




Fig. 318. View of the Transmitting Apparatus. 



connected on the back of the board with a third bind- 
ing post, at the lower end of the board. The third 
binding post is connected by a flexible cord with a 
wire, having a flattened end, and provided Avith a 
wooden handle. Sending a signal consists simply in 
drawing the flattened end of the wire with a uniform 



354 



HOME MECHANICS FOE AMATEUES 



speed down one of the grooves. The first two binding 
posts, being connected with the binding posts of the 
recording instrnnient and with a battery, when a signal 
is sent, the recorder is released automatically, and the 
detent is constantly withdrawn from the pin in the 
roller, so long as the signal is being sent, and the mes- 



A j 


1 

1 


1 


1 

U \ 

1 


2 1 


/ j 


^1 


/! 


p\ 


1 










1 
1 


1 


Si 


3 j 




A 




1 






C 


1 

i 


1 


1 

1 




4 : 


d\ 


1 


1 

1 


x\ 




6\ 


f X 


M 


s\ 


' 


? \ 


7 1 


f 1 


m\ 


1 


1 




s\ 




1 


T\ 




/ 1 


9 : 


G 1 


N\ 

1 












Fig. 319. How the Board is Wired for the Morse Alphabet. 

sage is thus recorded. When the signaling stops, the 
recorder is stopped by the action of the detent. 

Several transmitters may be connected with the 
recorder, and one wire in each case may be dispensed 
with, by grounding the other at each end. 

The recorder will run long enough to record a long 
signal or several short ones with one raising of the 
weight carried by the paper tape. 



HOME ]\IECHAXICS FOE AMATEUIiS 



355 



HOW TO :make telephones and tele- 
phone CALLS 

On January 30, 1894, the Bell telephone patent ex- 
pired and the invention became the property of the 
pnblic; so that whoever desires to do so can make, 
l)ny or sell telephones withont fear of infringing: the 




Fig. 320. Details of Construction of the Bell Telephone. 

rights of any one. This applies only to the hand in- 
strument now nsed as a receiver. Patents for other 
telephone apparatus still remain in force; but enough 
is available for actual service. With two hand instru- 
ments and a suitable call, telephonic communication 
may be maintained, under favorable conditions, over 



356 HOME MECHAXICS FOR AMATEURS 

a line eight or ten miles long, no battery being re- 
quired. 

To avoid the effects of induction and to secure the 
best results, a metallic circuit is required. It has been 
said, on good authority, that with hand telephones 
used as transmitter and receiver, conversation has 
been carried on between New A^ork and Chicago, using 
a metallic circuit formed of heavy copper wire and 
having very low resi^^tance. The words, it is said, 
were as distinct as where a transmitter is used, but the 
volume of sound was somewhat less. 

For the benefit of those Avho are desirous of making 
telephones for their own use, or for sale, we present 
perspective and sectional views of the latest and most 
improved form of telephone, all of the parts of which 
are shown in reduced size. 

The handle is made of hard rubber and the cap, 
which is also the mouthpiece, is of hard rubber. The 
diaphragm. A, is clamped at the edge between the cap 
or mouthpiece and the body of the handle. Very thin 
ferrotype plate has generally been used for the dia- 
phragm, but thin taggers iron, Avhen protected by a 
coat of shellac or other suitable varnish, is said to an- 
swer better. 

The compound magnet, B, used in the telephone, i.^ 
composed of four thin, flat bar magnets, a, arranged 
in pairs on opposite sides of the flat end of the soft iron 
pole piece, c, at one end, and the soft iron distance 
piece, d, at the opposite end, the magnets being 
clamped to these pieces, with like poles all in one di- 
rection. The space in the center of the magnet be- 
tween the pole piece and distance piece is filled with a 
strip, (J, of wood. 



HOME MECHANICS FOK AMATEUES 357 

The cjlindrical end of the distance lYwre which ex- 
tends beyond the mai>net is bored and tapped to re- 
ceive the screw by which tlie magnet is held in place 
in the handle. The cylindrical projecting end of the 
pole piece extends to within 1-100 or 2-100 of an inch of 
the diaphragm. In other words, it is placed as near the 
diaphragm as possible without being touched by the 
diaphragm when the latter vibrates. 

On the pole piece, c^ is placed a wooden spool, r, on 
which is wound No. 34 (Am. W. G. ) silk-covered cop- 
per wire. The wire fills the spool, and its ends are al- 
lowed to project one or two inches. The wire may be 
wound on the spool in either direction, and it is im- 
material which pole of the compound magnet adjoins 
the diaphragm. 

The resistance of the winding varies from 70 ohms 
as a minimum to 200 as a maximum. When the in- 
strument is to be used both as transmitter and receiver, 
and especially Avhen it is on long lines, the resistance 
should be 100 olims or more. No. 36 wire is used for 
the winding where the resistance is great. Of No, 34 
wire, 263 feet will be required for 70 ohms resistance. 
For 100 ohms, 373 feet are required. For 150 ohms, 
343 feet of No. 36 are required. 

In the end of the handle are inserted two binding 
posts, to which are attached insulated wires (No. 18), 
which extend toward the diaphragm, their free ends 
being soldered to the terminals of the fine ware on the 
spool, so that when the telephone is connected up in 
circuit Avitli other telephones the current will pass from 
one of the binding posts through one of the coarse 
Avires, through the fine wire coil, through the other 
coarse wire to the other binding post. 



358 



HOME MECHAXICS FOR AMATEURS 



The Bell telephone has a disk of flexible rubber 
slipped over the pole piece and over the ends of the 
coarse wires as a guard against short circuiting. A 
screw eye is inserted in the end of the telephone handle 
for suspending the instrument when not in use. 

This telephone, Avhen used in the manner suggested, 
requires neither battery nor induction coil. It is 
therefore easily connected up for use by electrically 
connecting the binding posts of one instrument with 
the binding posts of another. When a number of tele- 
phones are connected in the same line, the matter 




Fig. 321 



Single \Vire Circuit. 



is not quite so simi)le. There are many ways of ar- 
ranging the circuit ; we give diagrams of two, one for 
one line wire with ground connections, the other for 
a metallic circuit, Avith a separate circuit for calling. 

In the single wire circuit each instrument on the line 
is provided with a double switch cut into the line as 
shown in Fig. 321, the pivots of the switch arm a «', be- 
ing connected with the line wire. The switch arms 
are pivotally connected with a bar of insulating mate- 
rial, so that they will move together. The arms, a a'y 
mav l)e brought into contact with the points, d, (V , e. 



HOME MECHANICS FOR AMATEURS 



359 



('', and /. A magneto call box is connected with the 
points, d (/', and the arms, (/ a', are left normally on 
these points, as shown in dotted lines, so that when 
any magneto in the line is operated the others will 
ring. All on the circnit have a special call. 

The one called will know whether the signal comes 
from the east, west, north or south. Suppose it to 
come from the east, the switch is placed in the position 
shown in full lines. This cuts out the magnetos, 
grounds the western section of the line through the 
point, c, and connects the eastern section with one 




Fig. 323. Metallic Circuit. 



end of the telephone cord through the point, c\ the 
other telephone connection being grounded through 
the points, / e, and ground wire. If the call is from 
the west, the switch arms, a a', are brought into con- 
tact with the points, c' /. The arms, a a', are always 
left on the points, d, d'. Outside the terminal stations 
the line is connected with the ground or arranged as 
shown in Fig. 322, with the line grounded through the 
magneto or telephone. 

In the metallic circuit shown in Fig, 323, the termi- 
nal telcDhones are connected with the ends of the line 



360 HOME ]\IECHAX1CS FOK AMATEURS 

wires. Intermediate telephones are cut into the line 
hj means of a double switch, as shown in the cut, in 
which g shows the intermediate telephone cut out, h 
shows it connected with the east and i Avith the west. 

A third wire grounded at the ends, and including a 
magneto for each telephone, runs parallel with the 
metallic circuit. In this case all of the bells ring at 
once, and individual signals must be agreed upon. 

It is obvious that the information here given in re- 
gard to the construction of the telephone may be de- 
parted from in minor points, such as the construction 
of the handle and mouthpiece, but everything relating 
to the magnet, the coil, and the relation of the magnet 
and diaphragm, should be strictly followed. 

No telephone line is complete without a signal of 
some kind which will serve to attract the attention of 
a person in the vicinity of the instrument. A battery 
call answers very well for short distances, but for a dis- 
tance of from one to twelve miles or more, the battery 
has been found impracticable and the magneto call is 
generally employed. This instrument not only serves 
a good purpose in connection with the telephone, but 
it answers very well indeed for general signaling pur- 
poses. It is always ready for action, and does not in- 
volve the care of a battery. 

The line drawings presented herewith are one-third 
the actual size (linear measurement) of the instru- 
ment, and the perspective view is also one-third of the 
actual size; the only dimension not obtainable from 
the drawings is the depth of the signal box, which is 3 
inches. As all of the dimensions may be obtained from 
the engravings, it Avill be unnecessary to repeat them 
in the descriptive matter. 



HOME MECHANICS F01{ A^IATEUKS 



361 



The pole pieees, A A', between which armature, B, 
revolves, are formed of soft gray cast iron, with ears, 
a a, at the top and the ears, ?>, at the bottom, separat- 
ed by bars, C C, of non-mat>netic material, such as vul- 
canized fiber, hard rubber, or they may be made from 
hard wood, well varnished or saturated with paraffine 
to prevent them from shrinking or swelling. The pole 
pieces, A A', are clamped to the bars, C C, before they 
are bored out. They are bored out to loosely fit the 




Fig. 324. Magneto-Telephone Call. 

armature, B'. The pole pieces are provided with flanges, 
r, which rest upon the bottom of the casing and are 
drilled to receive screws, (/,, by means of which the mag- 



362 HOME MEC^HAXrCS FOE AMATEURS 

net is secured in place in the casini*. In the pole pieces, 
A A', above the ears, h, are drilled and tapped holes, (\ 
for receivino the stnds, /, by which the horseshoe mag- 
nets are secured to the pole pieces. The studs, /, are 
drilled for receiving keys, (j, by which the magnets are 
clamped in place. 

The compound magnet, 2, is composed of three flat 
steel bars forming U-shaped magnets, //, //', /r, with 
the space between the poles adapted to receive the pole 
pieces, A A'. The magnet Jr, fits over the adjoining 
edges of the magnets, // Jt\ and the three magnets are 
drilled to receive the studs, /, which extend through 
the magnets and into the pole pieces, the parts being 
clamped together by keys driven through the holes in 
the studs, as shown in the perspective view. 

The armature, B, is the Avell known H type of Sie- 
mens, made of soft gray cast iron, the shaft, i^ being 
cast integrally with the body of the armature. The 
part, j, which rec(4ves the wire is narrower and shorter 
than the polar extremities of the armature. The arma- 
ture is turned so that its convex sides will revolve very 
near but not in contact with the i3ole pieces. The 
shaft at the ends of the armature is turned, and to one 
end is fitted a sleeve, k, of insulating material (vul- 
canized fiber or hard rubber), on Avhich is placed a 
brass ring, I. In the inner side of the metallic ring, I, 
is inserted a stud, n, to which is soldered one terminal 
of the arnmture coil, the other terminal of which is 
soldered to a screw, 11, inserted in the shaft, i. The 
armature is wound in the same manner as an electro- 
magnet, the wire being carried around one arm of the 
armature until one-half of the wire is in place. It is 
then carried across the central portion of the arma- 



HOME MECHANICS FOK AMATEURS 



363 



ture and wound upon the other arm of the armature. 
The wire used is No. 34 silk-covered wire, there being 
about 1^ ounces of wire upon the armature, or enough 
to Qive it a resistance of 200 ohms. 





f 


7 


1 / 


n' 




t 


h 


h' 






c 


(d) 




G' 




1 


% J- 




Fig. 325. Details of Magneto-Call— the Generator. 

To the bar, (\ is secured a brass plate, E, b}^ means 
of screws which pass through the plate and into the 
bar. In the plate, E, opposite the center of the bore of 
the pole pieces, there is a bearing for one end of the 
shaft of the armature, and in the opposite or upper end 



364 HOME MECHAXICS FOPt AMATEUES 

of the brass plate, E, there is a bearing for the driving 
shaft, F. To the opposite end of the bar, C, and to 
the bar, C, is secured a plate, E', which is also pro- 
vided with bearings for the armature shaft and for 
the driving shaft. To the bar, C, is secured a curved 
spring, c, which bears upon the insulated ring, I, and 
this spring is connected by a wire, p^ with a binding 
post, q, at the top of the casing. 

Upon the end of the armature shaft, i^ outside the 
plate, E', is placed a pinion, r, and upon the shaft, F, 
is placed a spur wheel, s^ which engages the pinion, r. 
The shaft, F, is held in place in the machine by a screw^ 
inserted in the end of the shaft, and a washer held by 
the screw against the end of the shaft and bearing 
against the plate, E. The crank, C, by which the shaft, 
F, is turned, is screwed on to the end of the shaft 
through an aperture in the side of the casing. On 
the stud, f, projecting through the front of the magnet 
is placed a contact spring, t, which is clamped by the 
key which holds the magnet in place. 

The mechanism thus described comprises the mag- 
neto generator Avhich generates the alternating cur- 
rent required for operating the magneto bell. The 
machine is held in place in the casing by the screws, 
d, as already described, and the back of the casing is 
cut away to let the magnet, h^, into the back, thus 
economizing room. To the cover of the casing is at- 
tached the magneto bell, H, the magnet and armature 
of which are placed within the door, Avhile the bells 
are placed on the outside of the door, the hammer ex- 
tending through the door and between the bells. 

The body of the magneto call consists of a curved 
casting, u, which is secured to the inner face of the 



HOME MECHANICS FOR AMATEVHS 



365 



door and provided with loops, v v' , for receiving the 
soft iron pole pieees, w ic' , of the bell uiai»net. These 
pole pieces are held in place in the h>ops, r r', by 
screws passing throngh the side of the loop and bear- 
ing against the pole piece. The convex side of the 
casting, //, is provided with a rectangnlar notch, a', 
for receiving the L-shaped permanent magnet, 5', which 
is held in its place by a screw passing through the 




Fig. 326. Details of Magneto-Call— the Bell. 

magnet into the casting. To the L-shaped magnet, V, 
is secured a plate, c, which is bent twice at right 
angles, and in the bent ends of which are inserted pivot 
screws supporting the armature, d, which extends 
downward between the adjacent ends of the pole pieces, 
ic If'. The armature is covered by a strip, e', of cop- 
per, and in the end of the armature is inserted a wire, 



366 HOME MECHAXICS FOR AMATEURS 

/, carrying at its extremity a bell liaminer, g'. To the 
outer surface of the door, and on opposite sides of the 
bell hammer, are supported two bells, I, by studs, i'j 
projecting from adjustable plates, /, pivoted to the 
door at one end and provided with a curved slot at the 
opposite end for receiving a clamping screw, w^hich 
passes through the slot and into the door. By means 
of this device the bells may be adjusted so that each 
will receive a stroke cf the same power from the bell 
hammer, //'. 

The spools on the pole pieces, 7r w', contain about 
H ounces of No. 34 silk-covered copper Avire. They 
are wound in the same direction, and the inside ends 
are connected together. The outer end of one spool 
is connected with the upper hinge of the casing, which, 
in turn, is connected with the binding post, g'; the 
outer end of the remaining spool is connected with a 
strip, Ic, of copper attached to the door and connected 
with a plate, /', which comes into contact with the 
spring, /, when the door of the casing is closed. 

On the top of the casing there is a plug switch, 
Avhich also answers as a lightning arrester. The rear 
plate of the switch is provided with the binding post, 
m, which is connected with the ground. The binding 
posts, q q\ receive the ends of the line wire, the con- 
nections being made as showm in the section on the 
telephone, pages 358-360. 

When the call is placed at the end of the line the 
call box is grounded by inserting the plug, r, between 
the rear or ground plate and the front plate that is 
not connected with a line wire. When it is desired to 
cut the call box out of the line, the plug is inserted in 
the circular space between the two front plates, the 



HOilK MECHANIC'S I'Olt AMATEUKS 



367 



current passing from one end of the line through one 
of the binding post to the other portion of the line. 
When the i-.rnuiture, B, is turned by revolving the 
crank, (1, opposite ends are alternately presented to 
opposite poles, the consequence being that the rapid 
changes of magnetism in the armature induce alter- 
nate pulsations in the winding of the armature which 
operate the polarized bell of the instrument, also the 
polarized bell of the distant instrument, both being 
uormallv in the circuit. 

While talking over the line it is important to cut 
out the magnet on account of its resistance, and while 
signaling over long distances the signals are more 
effective if the telephones are cut out of the line. 

These machines can be purchased for |4, and we 
therefore doubt if it is profitable to undertake to make 
them ; however, they may be made without fear of legal 
complications, as they are not patented. 



THE END. 



Index 



^ Page 

Barometer 201 

Bas-Reliefs 69 

Battery, Primary 227 

Brass, Burnished 78 



Cabinet, Electrical 246 

Cabinet, Wall 40 

Caloric Engine 176 

Carving, Wood 26 

Centering 106 

Chasing 126 

Chime, Electric 237 

Chucking 112 

Cutters, Rotary 136 



D 

Drills and Drilling 99 

Dynamo, Edison 319 



E 

Electricity 227-367 

Electric Lighting 232 

Engines and Boilers, Model, 

169-184 
Engines, Running 175 



Page 

Fluted Work, Turning 10 

Frames 36 

Furnace, Electric 333 

G 

Gear Cutting 152 

Glass, Stained 51 

Grilles and Gratings 31 

Grinding and Polishing . , 92 

H 

Household Ornaments .... 31 
Hygroscope 198 



Index Plates 147 

Iron Work 73 

K 

Knives, Moulding 9 

Knurling 126 



Lamp, Electric Night 243 

Launch Motor, Electric... 298 

Lathe, Foot 96 

Lathe, Inexpensive 1-7 

Lathe, Woodworking on a. 8 



[369] 



370 



INDEX 



M PAOE 

Majolica, Imitation 49 

Metal Turning 119 

Metal Working .89-168 

Meteorology 187-205 

Microscope, The 218 

Model Making 155 

Motor, Edison 319 

Motor, Sewing Machine . . 278 
Motor, Simple Electric ... 259 

Motor, Small Electric 270 

Moulding Knives 9 

Moulding, Wood 11 

O 

Ornament, Feather 39 

Ornaments, Household ... 31 



P 

Plaster Objects 85 

Portiere 57 

Pseudo-Ceramics 41 

R 

Rain Gauge 193 

Repousse 61 

S 

Sawing, A Wrinkle in ... . 25 

Sawing Metals 89 

Saw, Scroll 12 

Saw Tooth 21 

Saw, Wood 8 



Paok 

Scroll Saw 12 

Silver Work 94 

Slide Rest 143 

Soldering 90 

Spinning Metals 160 

Stained Glass 51 

Steadying 106 

Steam Engine 169 



T 
Telegraph, Recording .... 848 
Telephone, How to Make.. 355 
Telescope, How to Make... 207 
Telescopes and Micro- 
scopes 207-225 

Thermometers 194 

Tooth, Saw 21 

Turning, Wood 6 

V 
Vases 41 

W 

Wall Ornaments 35 

Water Motor 181 

Weather Vane 189 

Whittling 16 

Wind Pressure Gauge .... 190 

Wire, Things in 75 

Wood Carving 26 

Wood Turning 6 

Wood-Working 1-29 

Work Bench 14 



Tools for Home Mechanics 



|j^:,^,|l|,|lfeil|l|l|lll|l|l|l|l|||l|l|l|l|l|l|l|lpi|l|l|l|l|^l|l|l|^^ 



E#> y:;,i:;^i;L?i.ij.^i.ij.iiij.,^i,i.^ 




Sargent's Planes 

are firsl-class goods throughout; well made and nicely 
finished. 

Sargent's Screw Drivers 

are superior tools that are appreciated by good mechanics. 

Sargent's Saws 

are perfect. There are no better saws than these in the 
world. 

Sargent's Squares 

are standard goods, carefully made from best steel. 



Sargent's Steel Hammers 



are made from solid cast steel. They are of the highest 
grade. 

Sargent's Augers and Bits 

are branded " U. S." They are meant for use day in 
and day out. 




SARGENT & CO. 

New Haven, Conn. ; New York ; Philadelphia ; Boston ; Chicago 



OUR Catalog 



GOODELL-PRATT COMPANY 



TOOLS 




Number u 



GPvEENFJELD.MASSU.SA. j 



snows 

128 

PAGES 

of 

Labor 
Saving 

Tools 



It will be sent FREE to any address on 
receipt of a request mentioning this book 



YOURS TRULY 

GOODELL-PRATT Cmm 

GREENFIELD, MASSACHUSETTS, U. S. A 




Tffi FRANKLIN 
MODEL SHOP 



^ Sets of Castings and Materials in the rough or semi- 
finished for the Franklin Model Gas Engine and the 
Franklin Model Dynamo. Send for Catalog M. 

^ The latest scientific novelty, Aeolicraft Model Yacht. 
Sails on a Tight Wire. Write for booklet. 





Franklin Horizontal Gas Engine 

^ Materials furnished for Constructing any of the Appara- 
tus or Devices described in this Dook. Prices on application. 

^ Electrical, Experimental and Fine Tool 
Work. Correspond- 
ence solicited. 




arse 



11 & Weed 




129-131 West 31st St. ^^ 

Franklin Vertical 
Gas Engine 



New York City 



The Most Popular Scientific Paper in the World 

Established 1845 Weekly, $3.00 a Year; $1.50 Six Months 



This unrivaled periodical is now in its 
fifty-ntnfh year, and, owing to its ever- 
increasing popularity, it enjoys tlie largest 
circulation ever attained by any scientific 
publication. Every number contains sixteen 
large pages, beautifully printxid, haudsonie- 
iy illustrated ; it pi-esents in popular style a 
descriptive record of the n)ost novel, in- 
teresting and important developments in 
Science, Arts and Manufactures. It shows 
the Progress of the World in respect to New 
Discoveries and Improvements, embracing 
Machinery, Mechanical Works, Engineering 
in all its branches, Chemistry, Metallurgy, 
Electricity, Light, Heat, Arcliitecture, 
Domestic Economy, Agriculture, Natural 
History, etc. It abounds in fresh and inter- 
esting subjects for discussion, thought or 
study. It provides material for experiment 
at home and in the laboratory, and it en- 
ables the intelligent reader to keep informed 
as to the industrial and scientific develop- 
ment of the country. To the inventor it is 
invaluable, as every number contains a com- 
plete list of all patents and trade-marks 
issued weekly from the Patent Office. It 
promotes Industry, Progress, Thrift and 
Intelligence in every community vvhere it 
circulates. 

The Scientific American should have a 
place in every Dwelling, Shop, Office, Schuol, 



or Library. Workmen. Foremen, Engineers, 
Superintendents, Directors, Presidents, Offi- 
cials, Merchants, Farmers, Teachers, Law- 
yers, Physicians, Clergymen — People in 
every walk and profession in life will derive 
satisfaction and benefit from a regular 
reading of the Scientific American. 

As an instructor for the young it is of 
peculiar advantage. Try it. Subscribe for 
yourself — it wiii bring you valuable ideas; 
subscribe for your sons — it will make them 
manly and self-reliant; subscribe for your 
workmen — it will jtlease and assist their 
labor; subscribe for your friends — it will be 
likely to give them a practical lift in life. 

If you want to know more about the paper 
send for "Fifteen Reasons Wliy You Should 
Subscribe to the Scientific American," and 
tor ''Five Reasons W/iy Inventors Should 
Subscribe to the Scientific American.'' Fifty- 
two numbers make 832 large pages, equal to 
3,328 ordinary magazine pages, and 1,000 
illustrations are published each year. Can 
you and your friends afford to be without 
this up-to-date periodical which is read by 
every class and profession? Remit .|!3.00 by 
postal order or check for a year's subscrip- 
tion, or .f 1.50 for six months. 

MUNN & CO.. Publishers 

361 Broadvk^ay, New York City 




Established 1876 



This journal is a separate publication 
from the Scientific American and is de- 
signed to extend and amplify the work 
carried on by the parent paper. In size and 
general make-up it is uniform therewith, 
covering sixteen pages of closely printed 
matter, handsomely illustrated. It has no 
advertising pages, and the entire space is 
given up to the scientific, mechanical and 
engineering news of the day. It differs from 
the Scientific American in that it contains 
many articles that are too long to be pub- 
lished in the older journal, or of a more 
technical nature. College professors and 
students find this edition especially adapted 
to their wants. It contains reports of the 
meetings of the scientific societies both in 
this country and abroad. It has many 
short notes concerning the electrical, engi- 
neering and general scientific news of the 
day, together with a column of selected for- 
muhv. Each number contains much foreign 
scientific news, and, when taken in connec- 
tion with the Scientific A.mebican. it ulaces 



before the reader a weekly review of the 
latest and most important discoveries and 
the most advanced technical and scientific 
work of the times all over the world. 

The price of the Supplement is .$5.00 a 
year, but where subscribers take both the 
Scientific American and the Scientific 
American Supplement a special combined 
rate of .f 7.00 for both is made if the papers 
are mailed to one address. Remit by postal 
order or chpck. All copies of the Supple- 
ment since January 1, 1870, are in print and 
can be supplied at the uniform price of 10 
cents each, thus enabling readers to obtain 
access to a most valuable source of infor- 
mation on almost every subject at the most 
moderate price. A large Sapvlemeni Cafa- 
loque giving a list of nearly 15,000 valuable 
I)apers will be mailed free to any one. 

Address 

MUNN & CO., Publishers 

361 Broadway, New York City 



IT will aid you in making a thorough 
application of the excellent instruc- 
tion in this book. In fact, we do not see 
how you can make much use of it unless 
you have our "A BOOK OF TOOLS" 
if interested in Metal Working, or 
"WOOD WORKER'S TOOLS," if 
Wood Working is what you are going to try. 

Either book sent on receipt of 25 cents 

The 





Chas. A. Strelinger Co. 

Publishing Department 

Detroit, Michigan 



T 



WENTIETH CENTURY 
METAL WORKING LATHES 

This is our 9" Screw Cutting 
Lathe in foot power style. 

The amateur or the practical 
mechanic can get efficient service 
from this tool. 

It is a very fine small Lathe, of 
unusual strength for its size, simple, 
accurate and durable. 

Has many features of special 
advantage and convenience. 

We also build an IT' Screw 
Cutting Lathe. Both are furnished 
in foot power or countershaft style, 
as may be desired. 

Complete details on request. 

B. F. BARNES COMPANY 

ROCKFORD. ILL., U. S. A. 




Ol L STONES 



Our leaders are: 

Lily White Washita 
Genuine Arkansas 
and India 




LILY WHITE WASHITA 




INDIA OILSTONE 



All shapes and sizes and 
for every purpose 

Send for Price List 

THE PIKE MANUFACTURING COMPANY 

PIKE 

Our Booklet entitled "Oil Stonesj 
How TO Select and Use Them,' 
contains information of "value to every 
user of edge tools. Write for it. 



NEW HAMPSHIRE 




GENUINE ARKANSAS 



For over 20 YEARS the name BUNNELL ^rlt^?!; 

Electrical Apparatus 

has been recognized as a guarantee of highest 
grade. If interested, write for Prices on 
whatever you want in the Electrical Line. 
Telegraph and Telephone Instruments and 
Supplies, Medical Apparatus, Bells, Pushes, 
Batteries, Wire, etc. We make a specialty of 
Telegraph and other Electrical Instruments for amateurs. Our BEEKO-PHONE is a high 
grade Indoor or Short-Distance Telephone, guaranteed satisfactory. $5.00 per pair. 

Catalogues Free. j j_j BUNNELL & CO., 20 Park Place, New York. 

PITTSBURG WHITE METAL CO. 

1 60 Leroy Street, New York *.'.' 1 739 Liberty Ave., Pittsburg, Pa. 
Manufacturers of 




We make 

the Best Metals 

Known 



BABBITT ^ 

ANTI-FRICTION 1 
MONOTYPE 

ELECTROTYPE } 
LINOTYPE 

SOLDERS I 

WHITE BRONZE j 



Metal 



F 



ORSTNER AUGER BITS 

FOR DISCRIMINATING AMATEURS 




Why? 



^ Because the FORSTNER is unique in being guided by its circular rim in^ead of its 
center. ^ It can, therefore, be used to bore ary arc. ^ A square hole can readily be 
bored with the FORSTNER by boring straight and then turning the bit at right angles. 
^ Recommended as a substitute for chisels, gouges, scroll-saws, or lathe tools in fine cabinet- 
work. Ask your dealer or write to the 

BRIDGEPORT GUN IMPLEMENT COMPANY 

BRIDGEPORT, CONN. 



Agency, 313 Broadway, 

New York City, N. Y 



SPECIAL MACHINERY built to order from 
Inventors' and Engineers' plans. Experimental 
work carried on under proper conditions. Special- 
ties made of the development of inventions and the 
making of models. 

FENN SADLER MACHINE COMPANY "^^f:"^' 



AMERICAN GUN CO 



Machine- Made Guns 

Interchangeable 
Parts 




^ The only American-made gun retailed at from $12 to $16, Made 
in five styles. If your dealer cannot supply them, write direct to 
THE H. & D. FOLSOM ARMS COMPANY. 314 Broadway, New York 
Send for Catalogue A 



PATENTS 

The Wealth of Nations 



A PATENT gives you an exclusive right to your 
invention for a term of seventeen years. You 
can sell, lease, mortgage it, assign portions of it, 
and grant licenses to manufacture under it. Our Patent 
system is responsible for much of our industrial progress 
and our success in competing in the markets of the world. 
The value of a successful Patent is in no degree commen- 
surate with the almost nominal cost of obtaining it. In 
order to obtain a Patent it is necessary to employ a 
Patent Attorney to prepare the specifications and draw 
the claims. This is a special branch of the legal profes- 
sion which can only be conducted successfully by ex- 
perts. For nearly sixty years we have acted as solicitors 
for thousands of clients in all parts of the world. Our 
vast experience enables us to prepare and prosecute 
Patent cases and Trade Marks at a minimum of expense. 
Our work is of one quahty, and the rates are the same to 
rich and poor. Our unbiased opinion freely given. 
We are happy to consult with you in person or by 
letter as to the probable patentability of your invention. 

^ Hand Book on Patents, Trade 
Marks, etc., Sent Free on Application 



MUNN & COMPANY 

SOLICITORS OF PATENTS 

Main Office 361 Broadway, New York 
Brancli Office, 625 F Street, Washington, D. C. 



WM. 



GARDAM 



A 



& SON One) 



45 to 51 Rose Street, Borough Manhattan, 
New York City 

Expert Mechanics 

^ We have exceptional facilities for doing all kinds of experimental, 
model and general machine work, especially adapted for the con- 
venience of the inventive public. ^ Private Departments for 
unprotected inventions vs^hile under construction. 



Gear Cutting 
Mechanical Drafting 
Light Manufacturing 

CORRESPONDENCE INVITED 



Punches and Dies 
Wood or Metal Patterns 
Special Machinery 

ESTABLISHED 1870 



V 



OLTMETERS, 

AMMETERS and 
VOLT-AMMETERS 



Compact, inex- 
pensive, accu- 
rate ; various 
ranges for gen- 
eral measure- 
ments, testing 
batteries, electric 
light, telephone 
and other cir- 
cuits. Special 
adjustment for 

determining resistance. Send for 

price-list. 

L. M. PIGNOLET 

80 Cortlandt Street, New York 




F. WEBER & CO. 

Manufacturers, Importers, Dealers 

Draughtsmen's and Engineers' Supplies 

SCIENTIFIC PUBLICATIONS AND HANDBOOKS 
ON ALL BRANCHES OF ART 

Mathematical Instruments and all kinds of 

Drawing Utensils. 

Blue Print and Drawing Papers. 

Liquid Drawing Inks and India Ink in sticks. 




ARTISTS' MATERIALS 



F.W£B£R&CO. 
'O/ST CO/LOi 

>S Chestnjjt SC^ 
P/f/L/^OeL PI! [A, 
CA HMINE. 



LITHOGRAPHERS" 
Supplies 
1:N(. RAVERS' 
Supplies 
ETCHERS- 
SUPPLIES 

GILDERS' 
Supplies 
Materials 

FOR Sign and 
Coach Painters 

St. T.ouis: Philadelphia: Baltimore: 

709 Locust St. 1 125 Chestnut St. 5 N. Charles St. 



Chemical and Physical Apparatus 

Microscopes, Telescopes, Lenses, Batteries, 
Magnets, Wire, Glass Tubing, Chemicals, and 
all other Supplies for the Amateur Scientist. 

APFEL- MURDOCH COMPANY 

82 LAKE STREET, CHICAGO 




SETS OF CASTINGS O F »^ 

MODEL ENGINES ^ 



ILL. CATALOGUE. 

^_^ ^ _^ALSQ TO O LS. 

GEAR WHEELS.a PARTS OF MODELS 



^^^\^W^NN B< ^\W;\U?^^^ 



TOOLS 



and 



Mechanical Supplies 

^___^^__^^______^_^_^_^^__^ of all kinds 

Tool Steel, Soft Steel, Iron, Brass, Copper, German Silver, Aluminum, etc., 
in Sheet, Wire, Tubes, and Bars, in Large or Small Quandties. ^ Brass 
or Iron Castings for Models or Light Machine Work. 

GOODNOW & WIGHTMAN, 132 Milk Street, Boston 




LUFKIN 

Steel Measuring 
Tapes and Rules 



ARE INDISPENSABLE FOR ACCURATE WORK 

Our Name stands for Accuracy and Reliability 

Made by 

THE LUFKIN RULE COMPANY. SAGINAW, MICH. 

For Sale Everywhere ::: Send for Catalogue 




4ta«M=«M* 




HAND and 
FOOT POWER 



MACHINERY 




J. M. MARSTON & CO. 

242 Ruggles Street, Boston, Mass., U. S. A. 



Send 

for 

Circular 



Revised and THE SCIENTIFIC AMERICAN 

^^^^ CYCLOPEDIA 

OF RECEIPTS, NOTES AND QUERIES 
15,000 RECEIPTS 734 PAGES 

Price, ^5.00 in Cloth. ^6.00 in Sheep. $6.50 in Half 
Morocco. Post Free. 
This work has been revised and enlarged. 

900 NEW FORMULAS 

The work is so arranged as to be of use not only to the 
specialist, but to the general reader. It should have a place 
in every home and workshop. 

Those who already have the Cyclopedia may obtain the 
I90I Appendix, Price, bound in cloth, $1.00 postpaid. 

MUNN & CO., Publishers, 361 Broadway, New York 



TWENTY-THIRD EDITION 

Experimental Science 

By GEORGE M. HOPKINS 

Revised and Greatly Enlarged. 2 Octavo Volumes^ I^IOO Pages. 

giO Illustrations. Cloth Bound^ Postpaid., $J 00. Half Morocco., 

Postpaid, $/.on. Or Volumes Sold Separately : Cloth., $3-00 

per Volume; Half Morocco., $^.00 per Volume. 

EXPERIMENTAL SCIENCE is so well known to many of our 
readers that it is hardly necessary now to gi^e a description o\ 
this work. Mr. Hopkins decided some months ago that it 
would be necessary to prepare a new edition of this work in order 
that the many wonderful discoveries of modern times might be fulh 
described in its pages. Since the last edition was published, wonder- 
ful developments in wireless telegraphy, for example, have been 
made. It was necessary, therefore, that a good deal of new matter 
should be added to the work in order to make it thoroughly up-to- 
date, and with this object in view some 200 pages haie been added. 
On account of the increased size of the work, it has been necessary 
to divide it into two volumes, handsomely bound in buckram. 

MUNN & CO., Publishers, 361 Broadway, New York 





Hawkins' Mechanical Drawing 




T 



HIS BOOK, as shown in 
illustration, is a self- 
instractor for home 
study and practice in the art 
of Mechanical Drawing for 
Engineers, Machinists, Elec- 
tricians, Metal Workers, and 
all interested in drafting for 
shop practice, and has been 
prepared in plain, practical 
language, and illustrated by 
the author of ' ' Hawkins' Edu- 
cational Works." The book 
is divided into 28 different subjects which comprise the fundamental 
principles of drawing, each heading being thoroughly treated. 

Thf.re are 320 pages, 3C0 illustrations and diagrams. The book is 

handsomely bound in green cloth, gold edges and titles, size 7 x \0}4 

inches print-^d on fine paper. Upon receipt of price the book will be sent 

to any address prepaid. Money returned if not as represented. Order to-day. 

Price, $2,00 Postpaid 

THEO. AUDEL & CO., Educational Book Publishers 
63 FIFTH AVENUE, NEW YORK 



BOOKS 



SCIENTIFIC AND TECHNICAL 
AND ALL STANDARD WORKS 



Will be furnished by the Scientific American Book Department, on receipt of author's name and 
tule. When ordering books remittance must accompany order. Send for our 

CATALOGUE, 116 PAGES, SENT FREE 

of Scientific and Technical Books; but remember that we can also furnish any work on History, 
Biography, Archaeology, Fiction, Travel, etc. We prepay postage or express charges on the sending 
of books to all places in the United Stntes, but books for foreign countries too large to go by foreign 
mail are sent by express at buyer's expense. Catalogue of Spanish works also mailed free to any address. 

MUNN & COMPANY, Publishers, 361 Broadway, New York 




GAS ENGINES, 
power to 1^2 



from 
horse 



SMALL 
% horse 

power. Model Electric Railways 
and Street Cars. Practical Working 
Toys. Gas Engine Igniter Dynamos. 



THE CARLISLE & FINCH CO. 

260 East Clifton Ave., Cincinnati, Ohio 
Send for Catalogue " B " 




SCIENTIFIC AMERICAN 

Building Monthly 

ESTABLISHED IN 1885 

Appeals to the Architect 
and Builder 

Because it illustrates the latest works of other 
architects and builders. Because it publishes 
timely articles and notes on ventilating, 
plumbing, legal matters, etc. Because it has 
interesting talks with prominent architects. 

Appeals to Those About 
to Build 

Because it publishes views of country 
houses of varying architectural styles and 

costs in all sections of the country, only illustrating those actually 

built. Full floor plans and descriptions are given. 

Price, $2.50 per Year Sample Copy, 25 Cents 

MUNN & CO., Publishers, 361 Broadway, New York 




Architects Should Subscribe 



Manufacturers Should Advertise 



MECHANICAL MOVEMENTS 

POWERS, DEVICES AND APPLIANCES 
By Gardner D. Hiscox, ME. 

Large 8vo, 402 Pages, 1649 Illustrations, with Descriptive Text. Price, $3.00 



a 



DICTIONARY cf Mechanical Movements, Powers, Devices, 
and Appliances, embracing an illustrated description of the great- 
est variety of mechanical movements and dev.ces in any language. 
A new work on illustrated mechanics, mechanical movements, devices, 
?nd appliances, covering nearly the whole range of the practical and 
inventive field, for the use of Machinists, Mechanics, Inventors, Engi- 
neers, Draughtsmen, Students, and all others interested in any way in 
the devising and operation of mechanical works of any kind. 

SEND FOR DESCRIPTIVE CIRCULAR 
MUNN & COMPANY, 361 Broadway, New York 



All Kinds of Light Machinery 

can be operated economically by any one able to KICK. 
A KICK of the lever starts the machine, and an occa- 
sional KICK keeps it going continuously. Our book of 
KICKS — will you ask for it ? We are making porta- 
ble forges on the same principle as our " Kick Drive." 




__ SLOTKIN & PRAGLIN 

Single Kick 210-212 Canal Street, New York 




Lathes 



Grade Laboratory Supplies and 
Apparatus for Experimental Work 

Get prices and description of the following: 

Wimshurst Machines and Auxiliary Apparatus 
Columbia Program Clock Crowell Aluminum Balance 

Columbia Micrometer Crowell Cabinets for Physics 

COLUMBIA SCHOOL SUPPLY CO. 

INDIANAPOLIS, IND. 




New Standard 
Dry Battery 

Standard of the U. S. Navy. Batteries 
for all uses by the dozen at wholesale 
prices. 

All sizes and prices accordingly. 

AGENTS WKITE QUICK I 






^^ 



"Hew Standard Electric Gas Lighter 

f 1.50 each. Good for one year in any home. New cells 
by mail, 40c. Quantities, J16 per hundred. 



Searchllghtit, Electric Gas Lighters, 
Automobile Lighters 




ELECTRIC SEARCHLIGHT 

Push the button, it lights. For all uses where candles, 
lamps, etc., are dangerous. $2 by mail or express, pre- 
paid. Extra liatteries, 35 cents. 

WM. ROCHE, Inventor and Sole Mannfaetnrer 
48 Vesey Street. New York, K. Y. 



The Progress of Invention 
In the Nineteenth Century 

By EDWARD W. BYRN. A.M. 

Large Octavo. 480 Pages. 300 Illustrations. 

Price, $3.00 by Mail, Postpaid. Half 

Red Morocco, Gilt Top, $4.00 

""pHE book gives a 
■'• most compre- 
hensive and cohe- 
rent account of the 
progress which dis- 
tinguishes this as the 
" golden age of in- 
vention," resulting 
in industrial and 
commercial develop- 
ment which is with- 
out precedent. A 
chronological calen- 
dar of the leading 
inventions is one of 
the most important 
features of the book, 
enabling the reader 

to refer at a glance to important inventions 
and discoveries of any particular year. 

MUNN & COMPANY, Publishers 
361 Broadway, New York 





■_J^& 






STARRETT TOOLS 

Are accurate enough for the finest mechanic, "handy" enough for the most 
inveterate tinker, and as low priced as good workmanship will permit. 
Our Illustrated Catalogue is free. You'll see something in it that you will want. 

THE L. S. STARRETT CO., ATHOL, MASS., U.S.A. 



oc 




k Work) 



We are Specialists 
in Clock Work and 
Electrical Attachments 
for Clocks. 

We make ihe only 
60-day Clock in the 
world, and the finest 
Automatic Calendar. 
Also Self-winding 
Electric Clocks, Min- 
ute Jumpers, Synchron- 
izers, Program Clocks, 
Reminders, Watchmen's Clocks, and 
Time Recorders. 

Experts in model work of all kinds. 
Send for Catalogue No. 853. 
The 

Prentiss Clock Improvement Co. 
Dept. 85, 49 Dey St., N.Y.City 




FOREIGN 
PATENTS 

DEPARTMENT of 
our business is devoted 
to securing foreign 
patents for American inventors. 
The vast foreign trade of the 
United States opens the markets 
of the world to the improve- 
ments which inventors in the 
United States are continually 
making in all the branches 
of industry. 

For advice concerning the protection 
of inventions abroad, address 

MUNN & CO., Attorneys 

361 Broadway, New York 




WE START YOU IW BUSINESS 

Does ycur spnre time bring jou both profit and 
pleasure I We can show von how to make it do 

this. Write fnr our booklet, " Plating fnr Profit 
and Pleasure." Special offer of complete equip- 
ment for those wishing to start a life business. 
Moderate prices, and time given to make pay- 
ments. A business edncation, along the line of 
Electroplating, given free to our patrons. The 
Par:tg<in Outifit, for household use and for doing 
first-class small work, from I1.75 up. \'aluable 
practical fornmlas given free with eacli outfit 
when requested. Weliavethe only non-poisonous 
plating compounds on the market. Amateurs 
can operate our outfits with safety and success. 
Mentioning Department will insure prompt 
attention. 

ELECTROTECHNIC & CHEMICAL CO. 

Dept. 14, 72 Washington Sq. South, New \«rk 



A Secure Position 

is yours if you are properly trained. What manufacturers and 
business men are calling for every day are trained men. Our 
booklet, " How to Earn More," contains interesting facts and 
helpful information. Send for a copy. IT'S FFIEE. 

Send for Catalogue 6 

THE CONSOLIDATED SCHOOLS 



DV ~1 !9'ii* 



56 Fif h Avenue, New York 



Our courses for 
home study include 

Engineering 

Architecture 

Mining 

Metallurgy 

Art 

Illustrating 

Decorating 

Journalism 

Bookkeeping 

Stenography and 

English Branches 



